Carbon-based foams with a three-dimensional (3D) structure can provide a lightweight template for the rational design and controllable preparation of metal oxide/carbon-based composite microwave absorption materials. In this study, the flake nickel cobaltate/reduced graphene oxide/melamine-derived carbon foam (FNC/RGO/MDCF) was successfully fabricated by solvothermal treatment combined with high temperature pyrolysis. The results indicated that RGO was evenly interspersed in the MDCF skeleton, providing an effective support for the load growth of FNC on its surface. The sample S3 had a minimum reflection loss (RLmin) of -66.44 dB at a thickness of 2.29 mm. When the thickness was 1.50 mm, the optimal effective absorption bandwidth (EAB) was 3.84 GHz. The analysis of the absorption mechanism of FNC/RGO/MDCF showed that the excellent absorption performance of FNC/RGO/MDCF was mainly dependent on the combined action of conduction loss, multiple reflection, scattering, interface polarization and dipole polarization.

The enrichment of chromium in the magnetic iron chromite (Fe(CrxFe1-x)2O4) phase is crucial for the recovery and recycling of chromium in stainless-steel pickling sludge. The kinetics and reaction mechanism of the solid-phase reaction between Fe3O4 and Cr2O3 were investigated using the diffusion couple method at 1473 K. Not only the diffusion behavior of Fe+2 ions and Cr3+ ions was elucidated, but also the solid solution behavior of Fe3+ ions was discussed clearly. The microscopic morphology of the diffusion couple and the change in the concentrations of Fe and Cr cations across the diffusion layers were analyzed using scanning electron microscopy and energy dispersive spectroscopy. The self-diffusion coefficients of cations were calculated based on the concentration profiles of Fe and Cr, with the results indicating that the self-diffusion coefficient of the Fe ions was consistently higher than that of the Cr ions. Additionally, a mixture of Fe3O4 and Cr2O3 was annealed at 1373–1473 K for 1–5 h, and the kinetic parameters were calculated by studying the phase content of the product. The phase content of Fe(CrxFe1-x)2O4 in the product was determined by Rietveld refinement of X-ray diffraction data, revealing that an activation energy (E) of 177.20 kJ/mol and a pre-exponential factor (B) of 610.78 min-1 of the solid-phase reaction that produced the Fe(CrxFe1-x)2O4 spinel.

Up to now, “Turn-on” fluorescence sensor exhibits promising potential toward the detection of heavy metal ions, anions, drugs, organic dyes, DNA, pesticides and other amino acids due to their simple, quick detection, high sensitivity and selectivity. Herein, a novel fluorescence method of detecting Cr3+ in an aqueous solution was described based on the fluorescence resonance energy transfer between rhodamine B and gold Nanoparticles. The fluorescence of RhB solution could be obviously quenched (“off” state) with the presence of citrate-stabilized AuNPs. However, upon addition of Cr3+ to AuNPs@RhB system, the fluorescence of AuNPs was recovered owing to the strong interaction between Cr3+ and the specific groups on the surface of citrate-stabilized AuNPs, which will lead to the aggregation of AuNPs (“on” state). At this monment, the color of the reaction solution turned to black. Under optimal conditions, the limit of detection (LOD) for Cr3+ was 0.95 nM (S/N=3) with a linear range of 0.164 nM ~ 3.270 μM. Furthermore, the proposed method exhibits excellent performances, such as rapid analysis, high sensitivity, extraordinary selectivity, easy preparation, switch-on fluorescence response and non-time consuming.

To improve the thermal and mechanical properties of yttrium tantalate (YTaO4) as a top coat ceramic of thermal barrier coatings (TBCs) for aeroengines, Y1-xTa1-xM2xO4 (M=Ti, Zr, Hf, x = 0.06, 0.12, 0.18, 0.24) middle entropy ceramics (MECs) were synthesized using a two-step sintering method, and their thermal conductivity, thermal expansion coefficients (TECs), and fracture toughness were investigated. An X-ray diffraction study revealed that the Y1-xTa1-xM2xO4 MECs were monoclinic, and the Ti, Zr, and Hf doping elements replaced Y and Ta. The variations in atomic weights and ionic radii led to disturbed atomic arrangements and severe lattice distortions, resulting in improve the phonon scattering and reduced thermal conductivity, with Y1-xTa1-xM2xO4 MECs (x = 0.24) exhibiting the lowest thermal conductivity of 1.23 W·m−1·K−1 at 900°C. The introduction of MO2 increased the configurational entropy and weakened the ionic bonding energy, leading to high thermal expansion coefficients (10.4 × 10−6 K−1, at 1400 °C). The reduction in the monoclinic angle β lowered the ferroelastic domain inversion energy barrier, and microcracks and crack extension toughening endowed Y1-xTa1-xM2xO4 MECs (x = 0.24) with the highest fracture toughness of 4.1 ± 0.5 MPa·m1/2. The simultaneous improvement of the thermal and mechanical properties in the MO2 (M = Ti, Zr, Hf) co-doped YTaO4 MECs, can be extended to other materials.

The application of liquid core reduction (LCR) technology in thin slab continuous casting can refine the internal microstructure of slab and improve production efficiency. In order to avoid the crack risk caused by large deformation during LCR process, and to minimize the thickness of the slab in bending segments, it is essential to determine the maximum theoretical reduction amount and corresponding reduction scheme for LCR process. With the SPA-H weathering steel as specific research steel grade, the distribution of temperature and deformation fields of the slab with LCR process were analyzed based on a three-dimensional (3D) thermal-mechanical finite element model. The high-temperature tensile test was designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperature, and the prediction model of the critical strain for two typical cracks, combining the effects of strain rate and temperature, were proposed by incorporating the Zener-Hollomon parameter. The crack risk with different LCR schemes were calculated based on the crack risk prediction model, and the maximum theoretical reduction amount for SPA-H slab with a transverse section of 145mm × 1600 mm is 41.8 mm, corresponding reduction amounts of segment 0 to segment 4 are 15.8mm, 7.3mm, 6.5mm, 6.4mm and 5.8mm, respectively.

Ti-6Al-4Zr-2Sn-6Mo is one of the most recent titanium alloys processed by Powder Bed Fusion – Laser Beam (PBF-LB). This alloy has the potential to replace Ti-6Al-4V in automotive and aerospace applications due to its superior mechanical properties, which are approximately 10% higher in terms of Ultimate Tensile Strength (UTS) and Yield Strength (YS) after appropriate heat treatment. In the as-built condition, the alloy is characterized by the presence of soft orthorhombic α’’ martensite, necessitating a post-processing heat treatment to decompose this phase and enhance the mechanical properties of the alloy. Usually, PBFed Ti6246 components undergo an annealing process that transforms the α’’ martensite into an α-β lamellar microstructure. The primary objective of this research was to develop a Solution Treating and Aging (STA) heat treatment tailored to the unique microstructure produced by the additive manufacturing process, with the aim of achieving an ultra-fine bilamellar microstructure reinforced by precipitation hardening. The study investigated the effects of solution temperature in the α-β field (ranging from 800 to 875 °C), cooling media (air and water), and aging time to determine the optimal heat treatment parameters for achieving the desired bilamellar microstructure. For each heat treatment condition, different α-β microstructures were found, varying in terms of the α/β ratio and the size of the primary α-phase lamellae. Particular attention was given to how these factors are influenced by increases in solution temperature and how microhardness correlates with the percentage of metastable β phase present after quenching. Tensile tests were performed on samples subjected to the most promising heat treatment parameters. A comparison with literature data revealed that the optimized STA treatment enhanced hardness and UTS by 13 and 23 %, respectively, compared to the annealed alloy. Fracture surface analyses were conducted to investigate the fracture mechanisms.

In this study, the manufacturing feasibility of Ti-6Al-4V samples by a combination of laser aided additive manufacturing with powder (LAAMp) and wire (LAAMw) was explored. Process study was firstly conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAMp and LAAMw, respectively. With the optimized process parameters, robust interfaces were achieved between the powder/wire deposits and the forged substrate, as well as between the powder deposit and wire deposit. Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V, where the powder deposit was dominated by finer α′ microstructure, and the wire deposit was characterized by lamellar α phase. The mechanisms of the microstructure formation and the corelation with mechanical behavior were analyzed and discussed. The mechanical properties of the interfacial samples, even without post-heat-treatment, can meet the requirements of the relevant Aerospace Material Specifications (AMS 6932). No fracture occurred within the interfacial area, further suggesting the robust interface. The findings in this study highlighted the feasibility of combining LAAMp and LAAMw in directly manufacturing Ti-6Al-4V parts in accordance with the dimensional resolution and deposition rate required, more importantly, achieving a sound strength and ductility balance at as-built condition.

The effective reuse of iron phosphate residue (IPR) is the key issue in the recycling of spent LiFePO4 batteries. The reduction leaching of IPR in H2SO4 solution by adding iron powder as reducing agent was investigated, and compared with direct leaching. The results show that the leaching rate of IPR reached 97% under the optimum reduction leaching conditions. Kinetic studies show that the activation energy for reduction leaching is 12.71 kJ/mol, while that of direct leaching is 21.57 kJ/mol. The reduction leaching time is reduced by half and the acid consumption is reduced by 30% compared to direct leaching with the same leaching rate. This work provides a scientific guidance to the treatment of iron phosphate residue from the recycling of spent LiFePO4 batteries

The increasing utilization of Infrared heat detection technology in military applications necessitates research on composites with enhanced thermal transmission performance and microwave absorption capabilities. This study satisfactorily fabricated a series of MoS2/BN-xyz composites (MoS2/BN-xyz composites are characterized by the weight ratio of MoS2 to BN in the composite, where xy:z denotes this ratio) through chemical vapor deposition, resulting in improved thermal stability and thermal transmission performance. The results showed that the remaining mass of MoS2/BN-101 was as high as 69.25wt% at 800℃ under air atmosphere, while maintaining a temperature difference of only 31.7℃ between the surface temperature and the heating source at a heating temperature of 200℃. Furthermore, MoS2/BN-301 exhibited an impressive minimum reflection loss value of −32.21 dB at 4.0 mm, along with a wide effective attenuation bandwidth (EAB)  ranging from 9.32 GHz to 18.00 GHz (8.68 GHz). Therefore, these simplified synthesized MoS2/BN-xyz composites demonstrate great potential as highly efficient contenders for enhancing both microwave absorption performance (MAP) and thermal conductance.

In this study, we developed an interpretable prediction framework to access the stretch formability of AZ31 magnesium alloys through combining the extreme gradient boosting (XGBoost) model with the sparrow search algorithm (SSA). Eleven features are extracted from the microstructures (e.g., grain size (GS), maximum pole intensity (Imax), degree of texture dispersion (μ), radius of maximum pole position (r), and angle of maximum pole position (A)), mechanical properties (e.g., tensile yield strength (TYS), ultimate tensile strength (UTS), elongation-to-failure (EL), and strength difference (∆S)), and testing conditions (e.g., sheet thickness (t) and punch speed (v)) in the data collected literature and experiments. By Pearson correlation coefficient and exhaustive screening methods, ten key features (not including UTS) can be identified as the final inputs, thus enhancing the accuracy of prediction accuracy of Index Erichsen (IE) value, which serves as the model's output. The newly developed SSA-XGBoost model exhibits a better prediction performance with the goodness of fitting (R²) value of 0.91 compared to traditional machine learning models. A new dataset (4 samples) is prepared to validate the reliability and generalization capacity of this model, and the errors between the predicted and experimental IE values are below 5%. Based on this result, the quantitative relationship between the key features and IE values are established by Shapley additive explanations method and XGBoost feature importance analysis. Imax, TYS, EL, r, GS, and ΔS significantly influence the IE value among 10 input features. This work offers a reliable and accurate tool for predicting the stretch formability of AZ31 magnesium alloys and provides insights to developing the high-formable magnesium alloys.

Given the surging demand for nickel and cobalt fueled by the rapid expansion of the electric vehicle industry, it is imperative to develop efficient and eco-friendly metallurgical routes for extracting these metals. This work introduces a sustainable and effective method for nickel and cobalt extraction from Ni-Co-Fe alloy powder, which was obtained from a limonitic laterite ore through selective reduction-magnetic separation. The leaching efficiencies of Ni, Co and Fe were 89.4%, 94.8% and 96.5%, respectively, under the leaching conditions of 3M H2SO4, 85°C and a liquid-to-solid ratio of 10 mL/g for 90 min. The incorporation of H2O2 enhanced the leaching efficiencies of Ni, Co and Fe. The redox potential of the solution plays a crucial role in the acid dissolution, with H2O2 modification enhancing Ni and Co dissolution. Phosphate precipitation facilitated the removal of iron from the leachate, achieving 96.1% iron removal ratio with only a 2.26% nickel loss.

The preparation of carbon-based electromagnetic wave (EMW) absorbers with thin matching thickness, wide absorption bandwidth, strong absorption intensity and low filling ratio remains a huge challenge. Metal-organic frameworks (MOFs) are widely considered to be ideal self-sacrificing templates for the construction of carbon-based EMW absorbers. In this work, bimetallic FeMn-MOFs derived MnFe2O4/C/Graphene composites were fabricated by a two-step route of solvothermal reaction and subsequent pyrolysis treatment. The results showed that the microscopic morphology of carbon skeletons evolved from loofah-like to octahedral, and then to polyhedron and pomegranate by adjusting the molar ratio of Fe3+ to Mn2+. Furthermore, when the molar ratio of Fe3+ to Mn2+ was 2:1, the obtained MnFe2O4/C/Graphene composite exhibited the best EMW absorption capacity. Specifically, the minimum reflection loss of -72.7 dB and the maximum effective absorption bandwidth of 5.1 GHz were achieved at a low filling ratio of only 10 wt%. In addition, the possible EMW absorption mechanism of MnFe2O4/C/Graphene composites was proposed. Therefore, the research results of this work would contribute to the construction of broadband and efficient carbon-based EMW absorbers derived from MOFs.

The effective construction of electromagnetic (EM) wave absorption materials with thin matching thickness, broad bandwidth and mighty absorption is the momentous solution to EM pollution, which is a hot topic in current environmental governance. In this study, N-rGO was firstly prepared by a facile hydrothermal method, and then high-purity 1T-MoS2 petals were homogeneously anchored to the wrinkled surface of N-rGO to fabricate 1T-MoS2@N-rGO nanocomposites. Multiple reflection & scattering of EM waves in distinctive multidimensional structure formed by 2D N-rGO & 1T-MoS2 microspheres consisting of plentiful thin nanosheets, mighty conduction loss derived from migration of massive electrons in a well-constructed conductive network formed by 1T-MoS2@N-rGO, and abundant polarization loss including dipolar polarization loss & interfacial polarization loss respectively originated from multitudinous electric dipoles & profuse heterointerfaces in 1T-MoS2@N-rGO, all of which gave 1T-MoS2@N-rGO nanocomposites superior EM wave absorption performances. The effective absorption bandwidth (EAB) of 1T-MoS2@N-rGO reached 6.48 GHz with a relatively thin matching thickness of 1.84 mm, and the minimum reflection loss (RLmin) of -52.24 dB was achieved at 3.84 mm. Additionally, the radar scattering cross section (RCS) reduction value of 1T-MoS2@N-rGO was up to 35.42 dB m2 at 0o, which further verified the huge potential of our fabricated 1T-MoS2@N-rGO nanocomposites in practical applications.

For realizing the application of electromagnetic wave absorption (EWA) devices in the marine humid environment, the bifunctional electromagnetic wave absorption materials with better EWA capacity and anti-corrosion character present an exploration significance and systematic research requirement. Through using low-cost, excellent magnetic and stable chemical characters of ferrite (BaFe12O19) and using high dielectric loss and excellent chemical inertia characters of nano-carbon clusters, a new type of nanocomposites with carbon nanoclusters encapsulating barium ferrite (BaFe12O19) was designed and synthesized by combining an impregnation method and a high-temperature calcination strategy. Furthermore, Ce-Mn ions were introduced into the BaFe12O19 lattice to improve the dielectric and magnetic properties of BaFe12O19 cores significantly, and the energy band structure of the doped lattice and the orders of Ce replacing Fe site were calculated and shown. Benefiting from Ce-Mn ion doping and carbon nanoclusters encapsulating, the composite material exhibits excellent dual functionality of corrosion resistance and electromagnetic wave absorption. When the BaCe0.2Mn0.3Fe11.5O19-C (BCM-C) was calcined at 600°C, the minimum reflection loss of -20.1 dB was achieved at 14.43 GHz. The Ku band’s effective absorption bandwidth (EAB) of 4.25 GHz was realized at an absorber thickness of only 1.3 mm. The BaCe0.2Mn0.3Fe11.5O19-C / Polydimethylsiloxane (PDMS) coating has excellent corrosion resistance in the simulated marine environment (3.5wt% NaCl solution). The |Z|0.01Hz value of BaCe0.2Mn0.3Fe11.5O19-C remains at 106 Ω after 12 soaking days. The successful preparation of barium ferrite composite encapsulated with carbon nanoclusters provides new insights for the preparation of multifunctional absorbent materials and the fabrication of absorbent devices applied in the marine humid environment in the future.

The commonly used trial-and-error method of biodegradable Zn alloys is costly and blindness. In this study, based on the self-built database of biodegradable Zn alloys, two machine learning models are established by the first time to predict ultimate tensile strengths (UTSs) and immersion corrosion rates (CRs) of biodegradable Zn alloys. A real-time visualization interface has been established to design Zn-Mn based alloys; a representative alloy is Zn-0.4Mn-0.4Li-0.05Mg. Through tensile mechanical properties and immersion corrosion rate tests, its UTS reaches 424 MPa, and prediction error is only 0.95%. CR is 73μm/year and prediction error is 5.5%, which elevates 50 MPa grade of UTS and owns appropriate corrosion rate. Finally, influences of the selected features on UTS and CR are discussed in detail. The combined application of UTS and CR model provides a new strategy for synergistically regulating comprehensive properties of biodegradable Zn alloys.

The microstructural characteristics of austenite in Ti microalloyed steel during continuous casting significantly influence the thermoplasticity, thereby affecting the quality of the slab. In this work, a δ-γ phase transfer and growth model of Ti microalloyed steel was established, which considered the grain boundary inhibition effect of Ti carbonnitrides and driving force generated by grain curvature. The inhibition of grain boundary migration by Ti carbonitrides is strongest in the early stage of δ growth. The pinning effect of Ti carbonitrides weakens with the temperature decreasing, which resulted in a higher grain growth rate. During the δ-γ phase transition, the primary austenite is formed and its size is determined by introducing the δ-γ transformation coefficient. In this stage, Ti carbonnitrides have little effect on austenite formed. Rapid grain growth of γ phase occurs immediately after the completion of the transformation into a g single phase. In this stage, an entire cross-section austenite growth prediction model for slab continuous casting has been established based on the phase transformation model, with a prediction error of ≤5%. Under the influence of Ti carbonitrides and cooling rate, the grain sizes at the surface and center are 1524 μm and 5592 μm, respectively, differing by a factor of 3.67. As the Ti content increases from 0.02% to 0.04%, the grain refinement at the center is most significant, with an average grain size reduction of 27.14%.

Hypoeutectoid steel is a crucial metal structural material, which is characterized by the coexisting microstructure of ferrite and pearlite. The intricate interplay among its composition, processing conditions, and resultant microstructure, driven by multi-phase competition and multi-component characteristics, significantly complicates the understanding of austenite decomposition kinetics and elemental diffusion mechanisms during phase transformations. In addressing these complexities, the current study delves into the effects of cooling rate, prior austenite grain size, and C content on the component distribution and microstructure evolution during the austenite decomposition process of hypoeutectoid steels. Using a multi-phase field model, it reveals that an increase in the cooling rate from 1.0 °C/s to 7.0 °C/s leads to a reduced ferrite proportion and finer pearlite lamellae spacing from 52% to 22%, and from 1.06 μm to 0.67 μm, respectively. Concurrently, a decreased PAGS from 25.23 μm to 8.92 μm enhances the phase transformation driving force, resulting in smaller average grain sizes of pearlite clusters and pro-eutectoid ferrite. Moreover, an increased C content from 0.22 wt.% to 0.37 wt.% decreases the phase transition temperature from 795 °C to 750 °C and enhances the pearlite phase proportion from 27% to 61%, concurrently refining the spacing of the pearlite layers from 1.25 μm to 0.87 μm. This work aims to shed light on the complex dynamics governing the microstructural transformations in hypoeutectoid steels, thereby facilitating their wider application across different industrial scenes.

Delafossite AgFeO₂ nanoparticles with a mixed hexagonal structure of 2H and 3R phases were successfully fabricated using a simple co-precipitation method. The resulting precursor was calcined at temperatures of 100, 200, 300, 400, and 500ºC to obtain the delafossite AgFeO₂ phase. The morphology and microstructure of the prepared AgFeO₂ samples were characterized using FESEM, XRD, TEM, BET, XAS, and XPS techniques. A three-electrode system was employed to investigate the electrochemical properties of the delafossite AgFeO₂ nanoparticles in a 3 M KOH electrolyte. The delafossite AgFeO₂ nanoparticles calcined at 100ºC (AFO100) exhibited the highest surface area of 28.02 m²∙g⁻¹ and outstanding electrochemical performance with specific capacitances of 229.71 F∙g⁻¹ at a current density of 1 A∙g⁻¹ and 358.32 F∙g⁻¹ at a scan rate of 2 mV∙s⁻¹. This sample also demonstrated the capacitance retention of 82.99% after 1000 charge/discharge cycles, with superior specific power and specific energy values of 797.46 W∙kg⁻¹ and 72.74 Wh∙kg⁻¹, respectively. These findings indicate that delafossite AgFeO₂ has great potential as an electrode material for supercapacitor applications.

Secondary aluminum dross (SAD) poses a significant risk due to its high AlN content, while simultaneously offering a rich source of recyclable aluminum. Therefore, to reduce environmental risks during aluminum extraction process, the thorough removal of AlN becomes a prerequisite. Meanwhile, the intricate aluminum components and expensive additives also pose challenges to the process. In this study, waste sodium acetate (WSA) is proposed as an environmentally friendly additive for the deep removal of AlN and the enhanced extraction of aluminum from SAD. Due to the exothermic decomposition of NaAc, the reaction can occur at as low as 850 oC. The AlN removal efficiency reached an impressive 94.19% after sintering, while the Al leaching efficiency in the subsequent leaching process attained 93.55%. Compared with the control, these efficiencies were significantly increased by 41.80% and 391.33%, respectively. The favorable results were contributed to the comprehensive transformation of aluminum species. The formation of soluble phases Na1.95Al1.95Si0.25O4 occurred during the destruction of Al2O3 layer surrounding AlN and the transformation of other aluminum components. Simultaneously, the exposed AlN underwent decomposition under the action of NaAc. Therefore, this study utilizes the decomposition properties of NaAc to provide an efficient and environmentally friendly new route for the removal of AlN and extraction of Al from SAD.

Obtaining high-performance and low-cost anode materials is the critical goal of superior sodium-ion batteries (SIBs). Herein, by chemical vapor deposition (CVD) and a specialized nanoporous Cu-Ni alloy catalyst, the high-yield porous carbon nanofibers (CNFs) anode materials are prepared (named as CNFs@Cu-Ni). Density functional theory (DFT) calculations indicate that the incorporation of Ni results in a shift of the d-band center of catalyst, specifically from -2.34157 eV to -1.93682 eV. This significant shift elucidates the remarkable adsorption capacity exhibited by the Cu-Ni catalyst towards C2H2, thereby facilitating the catalytic growth of high-performance CNFs. Ultimately, this approach achieves a superior yield of deposited carbon, reaching 258.6% after growth for 1 h. Additionally, The CNFs@Cu-Ni anode presents an outstanding discharge capacity of 193.6 mAh g−1 at 1 A g−1 over 1000 cycles, and it displays exceptional rate capability by maintaining a capacity of 158.9 mAh g−1 even at 5 A g−1 in ether-based electrolyte. Additionally, it also exhibits excellent performance in the CNFs@Cu-Ni//NVP full battery. The excellent battery performance can be attributed to the presence of abundant Na+ adsorption sites on the surface of CNFs@Cu-Ni electrode materials. This study presents a new concept for the advancement of high-performance carbonaceous electrode materials for SIBs.

The<001>orientation of the Goss texture aligned with the rolling direction is the most easily magnetized direction, effectively enhancing the magnetic properties of non-oriented silicon steel. In the present study, an ultra-thin high-silicon sheet of 0.2 mm with a strong Goss texture was successfully fabricated using a two-stage rolling method, achieving superior magnetic properties. The combination of suitable primary rolling reduction and intermediate annealing proved beneficial in promoting the formation of Goss texture. Electron back scatter diffraction (EBSD) was used to characterize micro-shear bands within deformed grains of secondary rolled sheets. Observations revealed that the recrystallized Goss nucleus originated from the Goss substructure of shear bands within deformed {111}<112>grains during the initial stages of recrystallization. The influence of stored energy and grain size on texture evolution was thoroughly investigated using quasi-in situ EBSD during recrystallization. In the initial stages, large deformed {111}<112>and near {111}<112>grains with high stored energy facilitated nucleation and growth of Goss and near-Goss grains within shear bands and reduced grain boundary nucleation. In the later stages, large deformed grains with low stored energy underwent a strain-induced grain boundary migration mechanism to nucleate. During the recrystallization, many recrystallized Goss and near-Goss grains clustered together, with Goss grains rotating towards near-Goss orientation. The resulting annealed ultra-thin 0.2 mm sheet with a pronounced Goss texture exhibited superior magnetic properties.

The present study was conducted to investigate the mechanisms through which nanobubbles enhance the flotation separation performance of galena from pyrite by examining the effects of nanobubbles on the surface properties of galena and pyrite and the interactions between mineral particles and air bubbles.  Various analytical techniques, including focused beam reflectance measurement (FBRM), three-phase contact line (TPCL) analysis, zeta potential and contact angle measurements, were employed.  It has been demonstrated that nanobubbles significantly enhanced the flotation recovery of galena and its flotation selectivity from pyrite, as compared to the conventional flotation process.  The preferential formation of nanobubbles on the galena surface, which is more hydrophobic than pyrite surface, further increased the surface hydrophobicity and agglomeration of galena particles.  The introduction of nanobubbles into the flotation system also increased in the maximum TPCL length and detachment length between the galena surface and bubbles, contributing to the enhanced flotation efficiency.

The dynamic recrystallization and dynamic precipitation of Mg-5Gd-3Sm(-1Zn)-0.5Zr alloy after hot compression deformation were analyzed by EBSD and TEM techniques. The dynamic recrystallization mechanisms were investigated. Calculated the deformation activation energy, established the constitutive equation, created a critical strain model. The results indicate that the presence of the Zn element enhanced the production of DRX, considerably reduces the strength of {0001} plane texture, and boosts the Schmidt factor of nonbasal plane slip. The Mg-5Gd-3Sm-0.5Zr alloy had a low degree of DRX and it was manifested as a monolayer of DRX grains at the grain boundaries, and was dominated by the DDRX mechanism. The Mg-5Gd-3Sm-1Zn-0.5Zr alloy had a high degree of DRX, which occurred in the form of multilayered DRX grains by the main mechanism of CDRX. Compared with the Mg-5Gd-3Sm-0.5Zr alloy, in addition to the Mg5(Gd, Sm) phase, the Mg-5Gd-3Sm-1Zn-0.5Zr alloy also introduced a new dynamic precipitation phase called (Mg, Zn)3(Gd, Sm) phase. The dynamic precipitation phase prevented grain boundary migration and dislocation motion, which promoted DRX nucleation and prevented the growth of recrystallized grains.

The evolution of microstructure and mechanical properties of WE43 magnesium alloy during multi-pass hot rolling was investigated. Results revealed that multi-pass hot rolling promoted the formation of small second phases and this was conducive to the multiple dynamic recrystallization, consequently improving the microstructure homogeneity and refining the average grain size to 8.83 μm from 34.3 μm of the initial material. Meanwhile, the rolling deformation rotated abundant grain c-axes toward the normal direction and one strong fiber texture developed. Owing to the fine-grained strengthening, second phase strengthening, and texture modification, the yield strength along the rolling direction (RD) was improved to 324 MPa in the Pass 3 sheet from 164 MPa in the initial material. In addition, the deformation mechanism distribution maps indicated that the yield strength anisotropy between the RD and the transverse direction (TD) was attributed to the effects of the texture component on the dominant mechanisms. During the tensile test, the dominant deformation mechanism was the prismatic slip affected by RD strong basal texture, while was less proportion of prismatic slip under the influence of TD weak basal texture. Compared to the basal slip, the higher critical resolved shear stress of prismatic slip made the increase in yield strength along the RD higher about 51MPa than that along the TD (RD: 160 MPa, TD: 109 MPa).

Traditional stealth materials do not fulfill the requirements of the high absorption rate of radar waves and low emissivity of infrared waves. Further, they cannot escape from multiple detection technologies, considerably threatening weapon safety. Therefore, a stealth material compatible with radar/infrared is designed based on the photonic band gap characteristics of photonic crystals. The radar stealth layer (bottom layer) is a composite material of carbonyl iron/silicon dioxide/epoxy resin, while the infrared stealth layer (top layer) is a one-dimensional photonic crystal structure in which germanium and silicon nitride are alternately and periodically stacked. Through composition optimization and structural adjustment, the effective absorption bandwidth of compatible stealth materials with a reflection loss of less than −10 dB has reached 4.95 GHz, and the average infrared emissivity achieved is 0.1063, indicating good compatible stealth performance. Theoretical analysis proves that the structural design of photonic crystals can produce infrared waves within the range of the photonic band gap, achieving a high transmittance of radar waves and low emissivity of infrared waves. Infrared stealth is achieved without affecting the absorption performance of the radar stealth layer, and the conflict between radar and infrared stealth performance is resolved. The objective of this paper is to aid in promoting the application of photonic crystals in compatible stealth materials as well as the development of stealth technology and in providing design and theoretical basis for related experiments and research.

Silver nanoparticles (Ag NPs) have attracted much attention in the field of biomaterials due to their excellent antibacterial property. However, the reducing and stabilizing agents used for chemical reduction of Ag NPs are usually toxic and may lead to water pollution. In this work, Ag NPs (31.2 nm in diameter) was prepared by using the extract of an agricultural waste, straw, as the reducing and stabilizing agent. Experimental analysis revealed that the straw extract contains lignin, the structure of which possess phenolic hydroxyl and methoxy groups, facilitating the reduction of silver salts into Ag NPs. The surfaces of Ag NPs were negatively charged due to the encapsulation of a thin layer of lignin molecules that prevented their aggregation. Interestingly, after adding the prepared Ag NPs into the precursor solution of acrylamide, free radical polymerization was triggered without the need of extra heating or light irradiation, resulting in the rapidly formation of an Ag NPs-polyacrylamide composite hydrogel. The inhibition zone test proved that the composite hydrogel possesses excellent antibacterial ability due to the presence of Ag NPs. The prepared hydrogel may find potential applications in fabrication of biomedical materials, such as antibacterial dressings.

Large-scale underground projects require precise in-situ stress information, and the acoustic emission (AE) Kaiser effect method currently provide lower costs and streamlined procedures. In this method, the accuracy and speed of Kaiser point identification are crucial. Thus, the integration of chaos theory and machine learning for the precise and rapid identification of Kaiser points constitutes the objective of the study. The intelligent model of the AE partitioned areas identification was established by phase space reconstruction (PSR), genetic algorithm (GA), and support vector machine (SVM). Then, the plots of model classification results were made to identify Kaiser points. We refer to this method of identifying Kaiser points as “The Partitioning Plot Method based on PSR-GA-SVM” (PPPGS). The PSR-GA-SVM model demonstrated outstanding performance, achieving a 94.37% accuracy rate on the test set, with other evaluation metrics also indicating exceptional performance. The PPPGS identified Kaiser points similar to the tangent-intersection method, with greater accuracy. Furthermore, in the classification model's feature importance score, the fractal dimension extracted by PSR ranked second after accumulated AE counts, confirming its importance and reliability as a classification feature. To validate practicability, the PPPGS were applied to in-situ stress measurement at a phosphate mine in Guizhou Weng'an, China, demonstrating good performance.

The environment-friendly and efficient selective separation of chalcopyrite and molybdenite presents a challenge in mineral processing. In this study, Gum Arabic (GA) was initially proposed as a novel depressant for the selective separation of molybdenite from chalcopyrite in flotation processes. The micro-flotation results indicated that GA exhibited a stronger inhibitory capacity towards molybdenite rather than chalcopyrite. At pH 8.0 with the addition of 20 mg/L GA, the recovery of chalcopyrite in the concentrate obtained from mixed minerals flotation was 67.49% higher than that of molybdenite. Furthermore, the mechanism of GA was systematically investigated by various surface characterization techniques. The contact angle tests indicated that the hydrophobicity of molybdenite surface significantly decreased after GA treatment, while there was no apparent change in the hydrophobicity of chalcopyrite surface. The Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) results indicate that the interaction force between GA and chalcopyrite was weak. In contrast, GA primarily adsorbed onto the surface of molybdenite through chemical chelation, with hydrogen bonding and hydrophobic interactions also possibly contributing. Pre-adsorbed GA could prevent BX from adsorbing onto the molybdenite. Scanning electron microscopy energy dispersive spectroscopy (SEM-EDS) analysis further indicated that GA primarily adsorbed onto the "face" of molybdenite rather than the "edge". Therefore, GA could be a promising molybdenite depressant and provide flotation separation of Cu–Mo.

Weathering steel has excellent corrosion resistance and is widely used in bridges, towers, railways, highways and other engineering that are exposed to the atmosphere for long periods of time. However, before forming stable rust layer, weathering steel is prone to issues such as rust liquid sagging and spattering, leading to environmental pollution and city appearance concerns. These factors limit the application and development of weathering steel. In this study, we developed a rapid and environmentally friendly method by introducing alloying elements, specifically investigating the role of tin (Sn) in the rapid stabilization of the rust layer in a marine atmospheric environment. In this work, we explored the rust layer formed on weathering low-alloy steel exposed to prolonged outdoor conditions and laboratory immersion experiments by EPMA, micro-Raman, XPS and electrochemical measurements. The results showed an optimal synergistic effect between Sn and Cr, which facilitated the accelerated densification of the rust layer. This beneficial effect contributed to enhancing the ability of the rust layer to resist Cl- erosion and improving the protection performance of the rust layer.

Bioleaching is confronted with problems, such as low efficiency, long production cycle length and vegetation destruction. In order to solve problems above, fly ash and low-grade copper sulfide ores were used to investigate bioleaching behaviors and bacterial community succession. Results showed that copper recovery, bacterial concentration, total proportion of main leaching bacteria including Acidithiobacillus ferrooxidans, Acidibacillus ferrooxidans and Leptospirillum ferriphilum, were improved though using appropriate dosage of fly ash. The maximum copper recovery of 79.87% and bacterial concentration of 7.08 × 107 cells·mL−1 were obtained after using 0.8 g·L−1 fly ash. Exclusive precipitation including Zn(Fe3(SO4)2(OH)6)2 and Mg(Fe3(SO4)2(OH)6)2 was found in sample added 0.8 g·L−1 fly ash, which reduced the effect of hazardous ions on bacteria and thus contributing to bacterial proliferation. Bacterial community structure was differentiated, which indicated difference between original inoculation and sample used 0.8 g·L−1 fly ash was less than others. Total proportion of the three microorganism above accounted for more than 95% in all tests, especially in sample with 0.8 g·L-1 fly ash up to 99.81%. Cl- and Ag+ contained in fly ash can act as catalytic agent, which contributed to conversion from smooth and dense passivation layer to sparse and scattered one, and therefore improving contact between ores, lixiviant and bacteria. Using appropriate dosage of fly ash showed prospects in bioleaching.

The demand for oil casing steel with ultra-high strength and excellent impact toughness for safe application in ultra-deep wells is pressing. Aiming at improving the combination of strength, ductility and impact toughness, the designed Cr-Mo-V micro-alloyed oil casing steel was quenched at 800°C, 900°C, 1000°C, followed by tempering at 600°C, 680°C, 760°C respectively to obtain distinct microstructures. The results showed that the microstructure of the samples quenched at 800°C followed by tempering consisted of untransformed ferrite and large undissolved carbides, which deteriorated both tensile strength and impact toughness significantly. For other conditions, the nucleated carbides and the boundaries are key factors that balance the tensile strength from 1226 MPa to 971 MPa and impact toughness from 65 J to 236 J. From the perspective of carbide, optimal precipitation strengthening is achieved with a small carbide size obtained by low tempering temperature of 600℃, while larger-sized carbides would significantly soften the matrix to improve the toughness but deteriorate the tensile strength. Additionally, an increase in prior austenite grain size with the corresponding enlarged sub-boundaries obtained by high quenching temperature substantially diminishes grain refinement strengthening, dislocation strengthening and the energy absorbed in crack propagation process, which is unfavorable to strength and toughness.

The equilibrium phase relations of the CaO-SiO2-TiO2-5 wt.% Fe3O4 system were experimentally investigated at 1400 °C in air. High-temperature equilibration-quenching techniques were employed in an electric MoSi2 resistance heated furnace, with phase composition analysis conducted using an Electron Probe Micro-Analyzer and X-ray diffraction. A single liquid region, liquid-solid phase equilibrium including liquid-tridymite, liquid-rutile, liquid-perovskite, liquid-wollastonite, as well as three-phase equilibrium of liquid-tridymite-rutile and liquid-rutile-perovskite are found. The 1400 °C isothermal sections of the CaO-SiO2-TiO2-5 wt.% Fe3O4 system in air were projected. The present experimental results exhibited good agreement with the calculation results obtained from FactSage.

Nowadays, force sensors play an important role in industrial production, electronic information, medical health and many other fields. Two-dimensional material-based filed effect transistor (2D-FET) sensors are competitive with nano-level size, lower power consumption and accurate response. However, few of them has the capability of impulse detection, which is a path function, expressing the cumulative effect of the force on the particle over a period of time. Herein, we fabricated the flexible PMMA gate dielectric MoS2-FET for force and impulse sensor application. We systematically investigated the responses of the sensor to constant force and varying forces, and achieved the conversion factors of the drain current signals (Ids) to the detected impulse (I ⃗). The applied force was detected and recorded by Ids with a low power consumption of ~30 nW. The sensitivity of the device can reach ~8000% and the 4×1 sensor array is able to detect and locate the normal force applied on it. Moreover, there was almost no performance loss for the device as left in the air for two months.

The control of oxygen is paramount in achieving high-performance titanium (Ti) parts by powder metallurgy such as metal injection molding (MIM). Herein, hydride-dehydride (HDH) Ti powders were modified by pre-oxidation to investigate the effect of oxygen variation on the characteristics of oxide layer on the particle surface and its resultant color feature. The results showed that the thickness and Ti dioxide level of the oxide layer on the HDH Ti powders were increased with the oxygen content, leading to the transition of color appearance from grey, brown to blue. In addition, the development of oxygen content was comprehensively studied during the MIM process using the gas-atomized (GA) Ti-6Al-4V powders. Particularly, the oxygen variation in the form of oxide layer, the change of oxygen content in the powders and the relevant parts were investigated during the process of kneading, injection, debinding and sintering. The oxygen variation was mainly concentrated in the sintering stage, and the content was increased with the increase of sintering temperature. This work provides a piece of valuable information on oxygen detecting, control and manipulation for the powder and processing in the industry of Ti powder metallurgy.

Simultaneously achieving high strength and high conductivity in Cu-Ni-Si alloys poses a significant challenge, which greatly constrains its applications in the electronics industry. This paper offers a new pathway for the improvement of properties, by preparation of nanometer lamellar discontinuous precipitates (DPs) arranged with the approximate same direction through a combination of deformation-aging and cold rolling process. The strengthening effect is mainly attributed to nanometer-lamellar DPs strengthening and dislocation strengthening mechanism. The accumulation of dislocations at the interface between nanometer lamellar DPs and matrix during cold deformation process can results in the decrease of dislocation density inside the matrix grains, leading to the acceptably slight reduction of electrical conductivity during cold rolling. The alloy exhibits an electrical conductivity of 45.32 %IACS, a tensile strength of 882.67 MPa, and a yield strength of 811.33 MPa by this method. This study can provide a guidance for the composition and microstructure design of Cu-Ni-Si alloy in the future, by controlling the morphology and distribution of DPs.

The effects of the Al content on the precipitation of nanoprecipitates, the growth of prior austenite grain (PAG), and the impact toughness in simulated coarse-grained heat-affected zones (CGHAZs) of two experimental shipbuilding steels after subject to high-heat input welding at 400 kJ·cm⁻¹ are studied. The base metals (BMs) of both steels contain three types of precipitates: Type-cubic (Ti, Nb)(C, N); Type Ⅱ-precipitate with cubic (Ti, Nb)(C, N) core and Nb-rich cap; and Type Ⅲ-ellipsoidal Nb-rich precipitate. In the BM of 60Al and 160Al steels, the number densities of the precipitates are 11.37 × 105 mm⁻² and 13.88 × 105 mm⁻², respectively. In 60Al steel, Type Ⅲ precipitates make up 38.12% of the total, whereas in 160Al steel, they account for only 6.39%. This variance in the amount of Type Ⅲ precipitates in 60Al steel reduces the pinning effect at the elevated temperature of CGHAZ, thereby facilitating PAG growth. The average PAG sizes in the CGHAZ of 60Al and 160Al steels are 189.73 μm and 174.7 μm, respectively. In 60Al steel, the low lattice mismatch between Cu2S, TiN and γ-Al2O3 facilitates the precipitation of Cu2S and TiN onto γ-Al2O3 during the welding, which decreases the number density of independently precipitated (Ti, Nb)(C, N) particles but increases the number density of γ-Al2O3-TiN-Cu2S particles. Thus, abnormally large PAGs are found in the CGHAZ of 60Al steel, reaching a maximum size of 1 mm. This presence of abnormally large PAGs in the CGHAZ of 60Al steel greatly reduces the microstructure homogeneity, consequently decreasing the impact toughness from 134 (0.016wt% Al) to 54 J (0.006wt% Al) at −40°C.

This study investigated the microstructure evolution of a cold-rolled (CR) and intercritical (IA) annealed medium-Mn steel (Fe-0.10C-5Mn) during uniaxial tensile test. In-situ observations under scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD) analysis were conducted to characterize the progressive TRIP (Transformation-Induced Plasticity) process and the associated fracture initiation mechanisms. These findings were discussed with local strain measurements by digital image correlation (DIC). The results indicated that the Lüders band formation in the steel was limited to a strain of 1.5%, mainly due to the the transformation of relatively large-sized blocky retained austenite (RA) into α’-martensite, retarding the yielding. The small-sized RA exhibited higher stability, progressively transforming into martensite and endowed stably extended Portevin-Le Chatelier (PLC) effect. The volume fraction of RA displaying a gradual decrease from 26.8% to 8.2% before fracture. In the late deformation stage, fracture initiation primarily occurred at the, austenite/martensite and ferrite/martensite interfaces as well as the rupture of ferrite phase.

This study investigated the effect of konjac glucomannan (KGM) on the flotation separation of calcite and scheelite. Micro-flotation tests showed that the floatability of calcite decreased significantly under the action of 50 mg/L KGM, while the impact on scheelite was negligible, resulting in a recovery difference of 82.53%. Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) analyses indicated that KGM was selectively adsorbed on the calcite surface. The zeta potential and UV-visible absorption spectroscopy test results revealed that KGM prevented the adsorption of sodium oleate on the calcite surface. X-ray photoelectron spectroscopy (XPS) analysis further confirmed that KGM achieved chemical adsorption on the calcite surface and formed Ca(OH)2. The density functional theory (DFT) simulation results were consistent with the flotation tests and measurement analyses, demonstrating that KGM had stronger adsorption performance on the calcite surface. This study provides a pathway for more sustainable and cost-effective mineral processing by utilizing the unique properties of biopolymers such as KGM to separate valuable minerals from gangue minerals.

Zinc oxide (ZnO) is an important functional semiconductor with wide direct bandgap about 3.37 eV. The solvothermal reaction has been usually employed to synthesize ZnO micro/nanostructures, which is inexpensive, simple and easy to implement. In addition, ZnO morphology engineering is desirable by changing slight condition in the reaction process, especially at room temperature. In this work, ZnO micro/nanostructures were synthesized in solution by changing amounts of ammonia addition at low temperature (even at room temperature). Ammonia can form Zn2+ complexes in precursor to control the reaction rate for morphology engineering of ZnO, such as nanoparticles, nanosheets, microflowers, and single crystals. Finally, the obtained ZnO was taken in optoelectronic application of ultraviolet detectors.

The wave-absorbing materials are kinds of special electromagnetic functional materials and have been widely used in electromagnetic pollution control and military fields. In-situ integrated hierarchical structure construction is thought as a promising route to improve the microwave absorption performance of the materials. In the present work, layer-structured Co-MOFs precursors were grown in-situ on the surface of carbon fibers with the hydrothermal method. After annealed at 500 °C under Ar atmosphere, a novel multiscale hierarchical composites (Co@C/CF) were obtained with the support of carbon fibers, keeping the flower-like structure. SEM, TEM, XRD, Raman and XPS were performed to analyze the microstructure and composition of the hierarchical structure, and the microwave absorption performance of the Co@C/CF composites were investigated. The results showed that the growth of the flower-like structure on the surface of carbon fiber was closely related to the metal-to-ligand ratio. The optimized Co@C /CF flower-like composites achieved the best reflection loss of -55.7dB in the low frequency band of 6-8 GHz at the thickness of 2.8mm, with the corresponding EAB of 2.1 GHz. The EAB of 3.24 GHz was achieved in the high frequency range of 12-16 GHz when the thickness was 1.5 mm. The excellent microwave absorption performance was ascribed to the introduction of magnetic components and the construction of the unique structure. The flower-like structure not only balanced the impedance of the fibers themselves, but also extended the propagation path of the microwave and then increased the multiple reflection losses. This work provides a convenient method for the design and development of wave-absorbing composites with in-situ integrated structure.

In this work, we realized a room-temperature NO2 gas sensor based on the Pt-loaded nano-porous GaN sensing material by thermal reduction method and co-reduction with the catalyzing of polyols. The gas sensor gained excellent sensitivity to NO2 of concentration range from 200 ppm to 100 ppb benefiting from the loading of Pt nano-particles, exhibited short response time (22 s) and recovery time (170 s) to 100 ppm NO2 at room temperature with excellent selectivity to NO2 compared to other gases. This phenomenon is attributed to the spillover effect and the synergic electronic interaction with semiconductor materials of Pt which not only provided more electrons for the adsorption of NO2 molecules but also occupied effective sites causing the poor sites for other gases. The low detection limit of Pt/NP-GaN is 100 ppb and the gas sensor still had fast response 70 days after fabrication. Besides, the gas sensing mechanism of gas sensor is further elaborated to figure out the reason leading to the improvement of properties. The significant spillover impact and oxygen dissociation of Pt provided advantages to its synergic electronic interaction with semiconductor materials leading to the development of gas properties of gas sensors.

Exploring efficient and nonprecious metal electrocatalysts of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial for developing rechargeable zinc-air batteries (ZABs). Herein, an alloying-degree control strategy is employed to fabricate nitrogen-doped carbon sphere (NCS) decorated with dual-phase Co/Co7Fe3 heterojunctions (CoFe@NCS). The phase composition of materials has been adjusted by controlling the alloying degree. The optimal CoFe0.08@NCS electrocatalyst displays a half-wave potential of 0.80 V for ORR and an overpotential of 283 mV at 10 mA cm-2 for OER in an alkaline electrolyte. The intriguing bifunctional electrocatalytic activity and durability is attributed to the hierarchically porous structure and interfacial electron coupling of highly-active Co7Fe3 alloy and metallic Co species. When the CoFe0.08@NCS material is used as air-cathode catalyst of rechargeable liquid-state zinc-air battery (ZAB), the device shows a high peak power-density (157 mW m-2) and maintains a stable voltage gap over 150 h, outperforming those of the benchmark (Pt/C+RuO2)-based device. In particular, the as-fabricated solid-state flexible ZAB delivers a reliable compatibility under different bending conditions. Our work provides a promising strategy to develop metal/alloy-based electrocatalysts for the application in renewable energy conversion technologies.

Cyanide is the most widely used reagent in gold production processes. However, cyanide is highly toxic and poses safety hazards during transportation and use. Therefore, it is necessary to develop gold leaching reagents that can replace cyanide. This paper introduces a method for synthesizing a gold leaching reagent. Sodium cyanate is used as the main raw material, with sodium hydroxide and sodium ferrocyanide used as additives. The gold leaching reagent can be obtained under the conditions of a mass ratio of sodium cyanate, sodium hydroxide, and sodium ferrocyanide as 15:3:1, synthesis temperature of 600 ℃, and synthesis time of 1 hour. This reagent has a good recovery effect on gold concentrate and gold-containing electronic waste. The gold extraction rate of calcination-desulfurized gold concentrate can reach 87.56%. For the extraction experiments of three types of gold-containing electronic waste, the gold extraction rate can reach over 90% after 2 hours. Furthermore, the reagent exhibits good selectivity towards gold. Component analysis indicates that the effective component in the reagent could be sodium isocyanate.

Sinter is the core raw material for blast furnace. Flue pressure is an important state parameter which affects the quality of sinter. To predict the flue pressure and take targeted adjustment measures, this paper studied the flue pressure prediction and optimization based on the SHAP. Firstly, sintering process data was collected and processed. A flue pressure prediction model was constructed after comparing different feature selection methods and model algorithms by SHAP+ET. The prediction accuracy of model within the error range of ± 0.25 kPa was 92.63%. SHAP analysis was used to improve the interpretability of prediction model. We analyzed the influence of various sintering operation parameters on flue pressure, the relationship between numerical range of key operation parameters and flue pressure, the effect of operation parameter combinations on flue pressure and the prediction process of flue pressure prediction model on a single sample. A flue pressure optimization module was constructed and analyzed when the prediction met the judgment conditions. Operating parameter combination was pushed. During the verification process, the flue pressure was increased by 5.87%, achieving a good optimization effect.

To effectively activate peroxymonosulfate (PMS) for methylene blue (MB) degradation purposes, S and Co co-doped carbon catalysts were prepared by pyrolysing MOF-71 and thiourea mixtures at 800oC at the mass ratio of MOF-71 to thiourea of 1:0.1. The effects of two different mixing routes were identified on the MB degradation performance. Particularly, the catalyst obtained by the alcohol solvent evaporation (MOF-AEP) mixing route could degrade 95.60wt% MB (50 mg/L) within 4 minutes(k=0.78), which was faster than that originated from the direct grinding way (MOF-DGP, 80.97wt%, k=0.39). X-ray photoelectron spectroscopy (XPS) showed that the Co-S site of MOF-AEP (43.39%) was less than that of MOF-DGP(54.73%), and the proportion of C-S-C in MOF-AEP(13.56%) was higher than that of MOF-DGP (10.67%). Density functional theory (DFT) calculations showed that the adsorption energy of Co for PMS was -2.94 eV when sulfur was doped as C-S-C on the carbon skeleton, which was higher than that when sulfur was doped next to cobalt in the form of Co-S bond (-2.86 eV). It was thus speculated that the C-S-C sites might contribute more in activating PMS compared with Co-S. Furthermore, the degradation parameters including pH and MOF-AEP dosage were also investigated. Finally, radical quenching experiments and electron paramagnetic resonance (EPR) measurements revealed that 1O2 might be the primary catalytic species whereas the •O2− might be the secondary ones in degrading MB.

The accurate prediction of molten steel temperature in the ladle furnace (LF) refining process has an important influence on the quality of molten steel and the control of steelmaking cost.. Extensive research has been conducted on establishing models to predict molten steel temperature. However, most researchers focus solely on improving the accuracy of the model, neglecting its explainability. This study aimed to develop a high-precision and explainable model and improve reliability and transparency of model. The eXtreme Gradient Boosting (XGBoost) and Light Gradient Boosting Machine (LGBM) were utilized, along with Bayesian optimization and Grey Wolf Optimization (GWO), to establish the prediction model. Different performance evaluation metrics and graphical representations were used to compare the optimal XGBoost and LGBM models obtained through different hyperparameter optimization methods with the other models. The findings indicated that the GWO-LGBM model outperformed other methods in predicting molten steel temperature, with a high prediction accuracy of 89.35% within the error range of ±5℃. Based on the tree structure visualization and SHapley Additive exPlanations analysis, the model's learning/decision process was revealed and the degree of influence of different variables on the molten steel temperature was clarified, which enhanced the explainability of the optimal GWO-LGBM model and provided reliable support for prediction results.

Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude. To investigate the correlation between the rock mass properties and maximum horizontal stress, the 3D stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted, a newly defined characteristic parameter ERP was proposed as an indicator for evaluating the structural properties of rock masses, and a fuzzy relation matrix was established using the information distribution method. The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth. There is no remarkable correlation between the elastic modulus and elastic modulus and depth, and the distribution of data points is scattered and messy. Moreover, there is no obvious relationship between the RQD and depth. The maximum horizontal stress σH is a function of rock properties, showing a certain linear relationship with the ERP at the same depth. In addition, the overall change trend of σH determined by the established fuzzy identification method increases with the increase of ERP, and the fuzzy identification method also demonstrates a relatively detailed local relationship between σH and ERP, and the predicted curve rises in a fluctuating way, which is in accord well with the measured stress data.

At present, the emerging solid-phase friction-based additive manufacturing technology, including friction rolling additive manufacturing (FRAM), can only manufacture simple single-pass components. In this study, multi-layer multi-pass FRAM-deposited aluminum alloy samples are successfully prepared using a non-shoulder tool head. The material flow behavior and microstructure of the overlapped zone between adjacent layers and passes during multi-layer multi-pass FRAM deposition are studied using the hybrid 6061 and 5052 aluminum alloys. The results showed that a mechanical interlocking structure was formed between the adjacent layers and adjacent passes in the overlapped center area. Repeated friction and rolling of the tool head led to different degrees of lateral flow and plastic deformation of the materials in the overlapped zone, which made the recrystallization degree in the left and right edge zones of the overlapped zone the highest, followed by the overlapped center zone and the non-overlapped zone. The tensile strength of the overlapped zone exceeded 90% of that of the single-pass deposition sample. It is proved that although there are uneven grooves on the surface of the overlapping area during multi-layer and multi-pass deposition, they can be filled by the flow of materials during the deposition of the next layer, thus ensuring the dense microstructure and excellent mechanical properties of the overlapping area. The multi-layer multi-pass FRAM deposition overcomes the limitation of deposition width and lays the foundation for the future deposition of large-scale high-performance components.

Fe-Ga alloys are potential for the new-generation magnetostrictive applications in sensors, transducers, and actuators due to the combination of large magnetostriction and good structural properties.<001>-oriented Fe-Ga sheets with large magnetostriction are required for improving the conversion efficiency under the ultra-high frequency magnetic field. Trace Tb element doping can simultaneously improve the magnetostriction and ductility of Fe-Ga alloy. However, the impact of trace Tb doping on the microstructure and magnetostriction of Fe-Ga thin sheets is an open question. In this paper, the effects of trace Tb addition on the secondary recrystallization and magnetostriction of Fe-Ga thin sheets are systematically studied by comparing the characteristics evolution of precipitation, texture, and nanoinclusions. The results indicates that trace Tb addition accelerates the secondary recrystallization of Goss grains due to the combined action of the bimodal size distributed precipitates, smaller grains, and more HEGBs in primary recrystallization. After quenching at 900 °C, the magnetostriction value in 0.07%Tb-doped Fe81Ga19 thin sheets increases 30% than that of Fe81Ga19 thin sheets. The increase of magnetostriction is attributed to the decrease in the number of Tb-rich precipitates and the higher density of the nanometer-sized modified-D03 inclusions induced by the dissolving of trace Tb elements after quenching. These results demonstrate a simple and efficient approach for preparing Fe-Ga thin sheets with excellent magnetostriction by a combination of trace RE element addition and conventional rolling method.

This study primarily investigates the rock fracture mechanism of bottom cushion layer blasting and explores the effects of the bottom cushion layer on rock fragmentation. It involves analysis of the evolution patterns of blasting stress, characteristics of crack distribution, and rock fracture features in the specimens. First, blasting model experiments are carried out using the dynamic caustics principle to investigate the influence of bottom cushion layers and initiation methods on the integrity of the bottom rock mass. The experimental results indicate that the combined use of bottom cushion layers and inverse initiation effectively protects the integrity of the bottom rock mass. Subsequently, the process of stress wave propagation and dynamic crack propagation in rocks was simulated using the Continuous-Discontinuous Element Method (CDEM) and the Landau explosion source model, with varying thicknesses of bottom cushion layers. The numerical simulation results indicate that with increasing cushion thickness, the absorption of energy generated by the explosion becomes more pronounced, resulting in fewer cracks in the bottom rock mass. This illustrates the positive role of the cushion layer in protecting the integrity of the bottom rock mass.

The binder phase performs critically on the comprehensive properties of cemented carbides, especially the hardness and fracture toughness relationship. There are strong motivations in both research community and industry for developing alternative binders to Co in cemented carbide system, due to the reasons such as price instability, property degeneration and toxicity. Herein, six kinds of high entropy alloys (HEA) including CoCrFeNiMn, CoCrFeMnAl, CoCrFeNiAl, CoCrNiMnAl, CoFeNiMnAl and CrFeNiMnAl were employed as the alternative binder for the preparation of WC-HEA cemented carbides through mechanical alloying and two-step spark plasma sintering. The impacts of HEA on the microstructures, mechanical properties and thermal conductivity of WC-HEA hardmetals were determined and discussed. WC-HEA hardmetals exhibited both superior hardness and fracture toughness to WC-Metal or WC-Intermetallic cemented carbides, indicating that HEA alloys were not only harder but also tougher in comparison with traditional metal or intermetallic binders. The HEA bonded hardmetals yielded thermal conductivities much lower than that of traditional WC-Co cemented carbide. The excellent HV-KIC relationship of WC-HEA facilitated the potential engineering structural application of cemented carbides.

The electrochemical behaviors of Sr on inert W electrode and reactive Zn/Al electrodes were systematically investigated in LiCl-KCl-SrCl2 molten salts at 773 K using various electrochemical methods. The chemical reaction potentials of Li and Sr on reactive Zn/Al electrodes were determined. It was found that Sr could be extracted by decreasing the activity of the deposited metal Sr on the reactive electrode, even though the standard reduction potential of Sr(II)/Sr was more negative than that of Li(I)/Li. The electrochemical extraction products of Sr on reactive Zn and Al electrodes were Zn13Sr and Al4Sr, with no co-deposition of Li observed. Based on density functional theory calculations, both Zn13Sr and Al4Sr were identified as stable intermetallic compounds of rich-Zn/Al phases. In LiCl-KCl molten salt containing 3wt% SrCl2, the coulombic efficiency of Sr in Zn electrode was approximately 54%. The depolarization values for Sr on Zn and Al electrodes were 0.864 V and 0.485 V, respectively, demonstrating a stronger chemical interaction between Zn and Sr. This work suggests that the use of reactive electrodes can facilitate the extraction of Sr accumulated in electrorefining molten salts, thereby enabling the purification and reuse of the salt and reducing the volume of nuclear waste.

Gels and conductive polymer composites including hydrogen bonds (HB) have developed into promising electromagnetic wave (EMW) absorption materials in response to different application scenarios. However, the relationship between conduction loss in EMW absorbing materials and charge transfer in HB remains to be explored. Herein, we construct a series of deep eutectic gels for fine-tuning the quantity of HB, by adjusting the ratio of choline chloride (ChCl) and ethylene glycol (EG). Due to the characteristics of deep eutectic gels, the impact of magnetic loss and polarization loss on EMW attenuation can be disregarded. The results indicate the quantity of HB increased first and then decreased with the introduction of EG, and HB-induced conductive loss exhibits similar patterns. At a ChCl and EG ratio of 2.4, G22-CE2.4 demonstrates the best EMW absorption performance (effective absorption bandwidth=8.50 GHz, thickness=2.54mm), which is attributable to the synergistic effects of excellent conductive loss and impedance matching generated by the appropriate number of HB. This work clarifies the role of HB in dielectric loss for the first time and offers a generic insight into the optimal design of supramolecular polymer absorbers.

Researchers have focused more on the depression mechanism of sulfite ions on copper activated sphalerite. The depression mechanism of sulfite ions on sphalerite and Pb2+ activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth understanding. Therefore, the depression mechanism of sulfite ions on sphalerite and Pb2+ activated sphalerite in the flotation separation of galena from sphalerite was further investigated by experiments and DFT calculations. Firstly, sulfite ions and oxygen were more likely to co-decompose xanthate treated by Zn2+ than xanthate treated by Pb2+, suggesting that the xanthate adsorbed on the surface of sphalerite was unstable. Secondly, sulfite ions were chelated with lead ions in solution to form PbSO3 and the hydrophilic PbSO3 was more easily adsorbed on sphalerite than galena. Thirdly, sphalerite was further inhibited by the product OH− in the oxidation process of sulfite ions, and OH− was more easily adsorbed on the surface of sphalerite in comparison with galena. However, sulfite ions hardly inhibited the flotation of galena and could promote the flotation of galena to some extent. Ultimately, sulfite ions could successfully achieve flotation separation of galena from sphalerite.

Carbon can change the phase components of low-density steels and influence the mechanical properties. In this study, a new method to control the carbon content and avoid the formation of δ-ferrite by decarburization treatment was proposed. The microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically examined. Crussard–Jaoul (C–J) analysis was employed to examine the work hardening characteristics during the tensile test. During decarburization by heat treatments, the carbon content within the austenite phase decreased, while Mn and Al were almost unchanged; this made the steel with full austenite transform into the austenite and ferrite dual phase. Meanwhile, (Ti, V) C carbides existed in both matrix phase and the mole fraction almost the same. In addition, the formation of other carbides restrained. Carbon loss induced a decrease in strength due to the weakening of the carbon solid solution. For the steel with the single austinite, the deformation mode of austenite was the dislocation planar glide, resulting in the formation of microbands. For the dual-phase steel, the deformation occurred by the dislocation planar glide of austenite first, with the increase in strain, the cross slip of ferrite took place, forming dislocation cells in ferrite. At the late stage of deformation, the work hardening of austinite increased rapidly, while that of ferrite increased slightly.

Copper, an essential metal for the energy transition, is primarily obtained from chalcopyrite through hydro and pyrometallurgical methods. The risk and harmfulness of this process represent the lack of safety for the environment and humans, so it is necessary to explore efficient and respectful hydrometallurgical methods. In this review article, emphasis is placed on current processes such as oxidative leaching, bioleaching, and pressure leaching that have shown efficiency in overcoming the complicated chalcopyrite network. The process of oxidative leaching epitomizes benign conditions within leaching media; nevertheless, the introduction of oxidizing agents confers extensive advantages. Bioleaching is a non-aggressive method that has shown a gradual increase in the contribution of copper and has been explored from primary and secondary sources. Pressure leaching, effective and selective for copper obtaining, becomes commercially more viable with increased research investments. This research also provides important data for advancing future research.

This work reveals the significant effects of cobalt (Co) on the microstructure and impact toughness in as-quenched high strength steels by both experimental characterizations and thermo-kinetic analyses. The results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without Co. In addition, the Co-bearing steel shows higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to 0.6. The improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by V1/V2 variant pair. The addition of Co induces a larger transformation driving force and a lower bainite start (BS) temperature, which contributes to the refinement of blocks and the increase of V1/V2 variant pair. These findings would be instructive for the composition, microstructure design and properties optimization of high strength steels.

This study investigates the microstructure and hydrogen absorption properties of a rare-earth high-entropy alloy, YGdTbDyHo. Results indicate that the YGdTbDyHo alloy has a microstructure of equiaxed grains, with the alloy elements distributed homogeneously. Upon hydrogen absorption, the phase structure of the high-entropy alloy changes from the solid solution with HCP structure to the high-entropy hydride with FCC structure, without any secondary phase precipitated. The alloy demonstrates a maximum hydrogen storage capacity of 2.33 H/M at 723 K, with enthalpy change (ΔH) of -141.09 kJ·mol-1 and entropy change (ΔS) of -119.14 J·mol-1·K-1. The kinetic mechanism of hydrogen absorption is hydride nucleation and growth, with an apparent activation energy (Ea) of 20.90 kJ·mol-1. Without any activation, YGdTbDyHo alloy can absorb hydrogen quickly (180 s at 923 K) with nearly no incubation period observed. The reason for 2.33 H/M is suggested that the hydrogen atoms occupy both the tetrahedral and octahedral interstice. These results demonstrate the potential application of High-Entropy Alloys (HEAs) as a high-capacity hydrogen storage material with a large H/M ratio, which can be used in the deuterium storage field.

The densely-distributed coherent nanoparticles (DCN) in steel matrix can enhance work-hardening ability and ductility of steel simultaneously. All the routes to this end can be generally classified into Liquid-Solid route (LSR) and Solid-Solid route (SSR). However, the formation of DCN structure in steel requires a long-time process and complex steps. So far, obtaining steel with coherent particle enhancement in a short time remains bottleneck, meanwhile some necessary steps are unavoidable. Here we show a high efficiency liquid-phase refining (LPR) process reinforced by dynamic magnetic field (DMF). The Ti-Y-Mn-O (TYMO) particles are around 3.53 ± 1.21 nm in average size, and can be obtained in just around 180 sec. These small nanoparticles are coherent with matrix, implying no accumulated dislocations between particle and steel matrix. Our findings have a potential application towards improving material machining capacity, creep resistance and radiation resistance.

Carbon materials are widely recognized as highly promising electrode materials for various energy storage system applications. Coal tar residues (CTR), as a type of carbon-rich solid waste with high value-added utilization, are crucially important for the development of a more sustainable world. In this study, we employed a straightforward direct carbonization method within the temperature range of 700-1000 °C to convert the worthless solid waste CTR into economically valuable carbon materials as anodes for potassium-ion batteries (PIBs). The effect of carbonization temperature on the microstructure and the potassium ions storage properties of CTR-derived carbons (CTRCs) were systematically explored by structural and morphological characterization, alongside electrochemical performances assessment. Based on the co-regulation between the turbine layers, crystal structure, pore structure, functional groups, and electrical conductivity of CTR-derived carbon carbonized at 900 °C (CTRC-900H), the electrode material with high reversible capacity of 265.6 mA·h g−1 at 50 mA·g−1, a desirable cycling stability with 93.8% capacity retention even after 100 cycles, and the remarkable rate performance for PIBs were obtained. Furthermore, cyclic voltammetry (CV) at different scan rates and galvanostatic intermittent titration technique (GITT) have been employed to explore the potassium ions storage mechanism and electrochemical kinetics of CTRCs. Results indicate that the electrode behavior is predominantly governed by surface-induced capacitive processes, particularly under high current densities, with the potassium storage mechanism characterized by an "adsorption-weak intercalation" mechanism. This work highlights the potential of CTR-based carbon as a promising electrode material category suitable for high-performance PIBs electrodes, while also provides valuable insights into the new avenues for the high value-added utilization of CTR.

The local structure and thermophysical behavior of Mg-La liquid alloys were in-depth understood using deep potential molecular dynamic (DPMD) simulation driven via machine learning to promote the development of Mg-La alloys. The robustness of the trained DP model was thoroughly evaluated through several aspects, including root-mean-square errors (RMSEs), energy and force data, and structural information comparison results, the results indicating the carefully trained DP model is reliable. The component and temperature dependence of the local structure in the Mg-La liquid alloy was analyzed. The effect of Mg content in the system on the first coordination shell of the atomic pairs is the same as that of temperature. The pre-peak demonstrated in the structure factor indicates the presence of a medium-range ordered structure in the Mg-La liquid alloy, which is particularly pronounced in the 80% Mg system and disappears at elevated temperatures. The density, self-diffusion coefficient, and shear viscosity for the Mg-La liquid alloy were predicted via DPMD simulation, and the evolution patterns with Mg content and temperature were subsequently discussed, and a database was established accordingly. Finally, the mixing enthalpy and elemental activity of the Mg-La liquid alloy at 1200 K were reliably evaluated, which provides new guidance for related studies.

A superhydrophobic and corrosion-resistant LDH-W/PFDTMS composite coating was prepared on the surface of Mg alloy. The LDH-W/PFDTMS composite comprised of a tungstate-intercalated (LDH-W) underlayer that was grown at a low temperature (versus hydrothermal reaction condition) under atmospheric pressure and a polysiloxane outer layer obtained in a solution containing perfluorodecyltrimethoxysilane (PFDTMS) by a simple immersion method. The successful intercalation of tungstate into the LDH phase and the following formation of the polysiloxane layer were confirmed by the X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the LDH-W film before and after PFDTMS modification was evaluated by electrochemical impedance spectroscopy (EIS), Tafel curves, and immersion experiments. Compared with the pure LDH-W film, the LDH-W/PFDTMS coating exhibited significantly enhanced corrosion protection for Mg alloy, with no apparent signs of corrosion after exposure to a 3.5wt% NaCl solution for 15 days. The static contact angle and water repellency tests of the LDH-W/PFDTMS coating demonstrated the superior superhydrophobicity and self-cleaning ability for water and several common beverages in daily life. These results guide the preparation of superhydrophobic and corrosion-resistant LDH-based composite coatings on Mg alloy surfaces under relatively mild reaction conditions.

Microstructure, texture and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures (260 ℃ and 320 ℃), extrusion ratios (10:1, 15:1 and 30:1) and extrusion speeds (3 mm/s and 6 mm/s), respectively. The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy, and the second phase showed streamline distribution along the extrusion direction (ED). With extrusion temperature increased from 260 ℃ to 320 ℃, the microstructure, texture and mechanical properties of alloys changed slightly. The DRX degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 15:1 and 30:1, and the strength gradually decreased but elongation (EL) increased. With the extrusion speed increased from 3 mm/s to 6 mm/s, the grain sizes and DRX degree increased significantly, and both samples presented the typical<21 1="">-<112 3="">rare-earth (RE) textures. The alloy extruded at 260 ℃ with extrusion ratio of 10:1, extrusion speed of 3 mm/s showed the best comprehensive properties with tensile yield strength (TYS) of 213 MPa and EL of 30.6%. After quantitatively analyzing the contribution of strengthening mechanisms, it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening contributions. These results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.

BiVO4 porous spheres modified by ZnO were designed and synthesized using a facile two-step method. The resulting ZnO/BiVO4 composite catalysts have shown remarkable efficiency as piezoelectric catalysts for degrading Rhodamine B (RhB) under mechanical vibrations, they exhibit superior activity compared to pure ZnO. The 40% ZnO/BiVO4 heterojunction composite displayed the highest activity, along with good stability and recyclability. The enhanced piezoelectric catalytic activity can be attributed to the formation of an Ⅰ-scheme heterojunction structure, which can effectively inhibit the electron-hole recombination. Furthermore, hole (h+) and superoxide radical (·O2-) are proved to be the primary active species. Therefore, ZnO/BiVO4 stands as an efficient and stable piezoelectric catalyst with a broad potential application in the field of environmental water pollution treatment.

To effectively investigate the impact of composite relationship of Mxene (Ti3C2Tx) and nano-FeCoNi magnetic particles on the electromagnetic absorption properties of composite, three sets of Mxene (Ti3C2Tx)@nano-FeCoNi composite materials with Mxene content of 15mg, 45mg, and 90mg were prepared with in-situ liquid phase deposition. The microstructure, static magnetic properties, and electromagnetic absorption performance of these composites were studied. The results indicate that the Mxene@nano-FeCoNi composite material was primarily composed of face-centered cubic crystal structure particles and Mxene, with spherical FeCoNi particles uniformly distributed on the surface of the multilayered Mxene. The average particle size of the alloy particles was approximately 100 nanometers, exhibiting good dispersion without noticeable particle aggregation. With the increase of Mxene content, the specific saturation magnetic and coercivity of the composite initially decrease and then increase, displaying typical soft magnetic properties. In comparison with FeCoNi magnetic alloy particles, the addition of Mxene causes an increasing trend in the real and imaginary parts of the dielectric constant of the composite, while the real and imaginary parts of the magnetic permeability exhibit a decreasing trend. The inclusion of Mxene enhances the dielectric loss but reduces the magnetic loss. Additionally, the dielectric loss and magnetic loss performance of the composite material do not show a linear function relationship with the addition of Mxene. Both the FeCoNi magnetic alloy particles and the Mxene@FeCoNi composite material exhibit polarization relaxation loss, and it was found that eddy current loss was not the main mechanism of magnetic loss. The material attenuation constant increases with the addition of Mxene, while the impedance matching decreases. Moreover, the maximum reflection loss increases and the maximum effective absorption bandwidth decreases with the addition of Mxene. When the Mxene addition was 90mg, the composite material exhibits a maximum reflection loss |RLmax| of 46.9dB with sample thickness of 1.1mm, and a maximum effective absorption bandwidth of 3.60GHz with sample thickness of 1.0mm. The effective absorption bandwidth of the composite material shows a decreasing trend with the corresponding sample thickness as the Mxene addition increases, reducing by 50% from 1.5mm without Mxene addition to 1mm with 90mg Mxene addition. These findings provide valuable insights for optimizing absorption coating thickness and weight.

Exploring high-efficient and broadband microwave absorption (MA) materials with corrosion resistance and low cost is urgently needed for widely practical applications. Herein, the natural porous attapulgite (ATP) nanorods embedded with TiO2 and polyaniline (PANI) nanoparticles are synthesized via heterogeneous precipitation and in-situ polymerization. The obtained PANI-TiO2-ATP one-dimensional nanostructures can intertwine into three-dimensional conductive network, which is favored for the energy dissipation. The minimum reflection loss (RLmin) of PANI-TiO2-ATP coating (20wt%) reaches -49.36 dB at 9.53 GHz，and the effective absorption bandwidth (EAB) can reach 6.53 GHz with a thickness of 2.1 mm. The excellent microwave absorption properties are attributed to the interfacial polarization, multiple losses mechanisms and good impedance matching induced by the synergistic effect of PANI-TiO2 nanoparticle shells and ATP nanorods. In addition, salt spray and Tafel polarization curve tests reveal that the PANI-TiO2-ATP coating shows outstanding corrosion resistance performance. This study provides a low-cost and high efficiency strategy to construct one dimensional nano-networks composites for microwave absorption and corrosion resistance applications using natural porous ATP nanorods as a carrier.

Influence of Nb-V microalloying on hot deformation behavior and microstructures of medium Mn steel (MMS) was investigated by uniaxial hot compression tests. By establishing the constitutive equations for simulating the measured flow curves, we successfully constructed deformation activation energy (Q) maps and processing maps for identifying the region of flow instability. We may conclude the following consequences as the Nb-V alloying of MMS: (i) The critical strain is increased and the increment diminishes with the increasing deformation temperature, suggesting that NbC precipitates could retard dynamic recrystallization (DRX) in MMS more than the solute Nb; (ii) The deformation activation energy of MMS is significantly increased and even more than high Mn steels, suggesting that it retards DRX more than high content of Mn; (iii) The hot workability of MMS is improved by narrowing the hot processing window for the unstable flow stress, in which the mixed presence of both fine recrystallized and coarse unrecrystallized grains has been confirmed.

Currently, the Al2O3 content in the high-alumina slag systems within blast furnaces is generally limited to 16-18.5wt%, making it challenging to overcome this limitation. Unlike most studies that concentrated on managing the MgO/Al2O3 ratio or basicity, this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO‐MgO‐Al2O3‐SiO2 slag system, providing theoretical guidance and data to facilitate the application of high-alumina ores. The results revealed that the viscosity first decreased and then increased with higher MgO substitution, reaching a minimum at 15mol% MgO concentration. FTIR results found that the depths of the troughs representing [SiO4] tetrahedra, [AlO4] tetrahedra, and Si-O-Al bending became progressively deeper with increased MgO substitution. Deconvolution of the Raman spectra showed that the average number of bridging oxygens per Si atom and the Q3/Q2 ratio increased from 2.30 and 1.02 to 2.52 and 2.14, respectively, indicating a progressive polymerization of the silicate structure. XPS results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration, whereas bridging oxygen and free oxygen contents increased. Structural analysis demonstrated a gradual increase in the degree of polymerization of the tetrahedral structure with the increase in MgO substitution. However, bond strength is another important factor affecting the slag viscosity. The occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the [SiO4] and [AlO4] tetrahedral structures by CaO and MgO.

Using SiC nanowires (SiC_NWs) as the substrate, the reflux-annealing method and electro-deposition-carbonization technique were sequentially applied to integrate SiC nanowires with magnetic Fe₃O₄ nanoparticles and amorphous nitrogen-doped carbon (NC), resulting in the fabrication of SiC_NWs@Fe₃O₄@NC nanocomposite. Comprehensive testing and characterization of this product have provided valuable insights into the impact of structural and composition changes on its electromagnetic wave absorption performances. The optimized SiC_NWs@Fe₃O₄@NC nanocomposite, containing a 30 wt% filler content and a matching thickness of 2.03 mm, demonstrates exceptional performance with a minimum reflection loss (RL_min) of -53.69 dB at 11.04 GHz and an effective absorption bandwidth (EAB) of 4.4 GHz. This investigation thoroughly elucidates the synergistic effects of the enhanced nanocomposites on electromagnetic wave absorption, drawing on theories of multiple scattering, polarization relaxation, hysteresis loss and eddy current loss. Furthermore, a multi-component electromagnetic wave attenuation model has been established, providing valuable insight for designing novel absorbing materials and enhancing their absorption performances. This research demonstrates the significant potential of the SiC_NWs@Fe₃O₄@NC nanocomposite as a highly efficient electromagnetic wave absorbing material, with potential applications in various fields, such as stealth technology and microwave absorption.

Pt-based nanocatalysts have remarkable prospect for industry. However, the low loading of Pt with excellent performance for efficient and stable nanocatalysts still remains highly challenging. Here, nanocatalysts with ultralow Pt content and excellent performance supported on carbon black are designed by in-situ synthesis. These ~2 nm particles uniformly and stably dispersed on carbon black due to the strong s-p-d orbital hybridizations between carbon black and Pt which suppressed the agglomeration of Pt ions. This unique structure is beneficial for the hydrogen evolution reaction. The catalysts exhibited remarkable catalytic activity for hydrogen evolution reaction with a potential of 100 mV at 100 mA cm-2, comparable to commercial Pt/C; and mass activity (1.61 A/mg) is four times higher than that of commercial Pt/C (0.37 A/mg). The ultralow Pt loading of 6.84wt% paves the way for the development of next generation electrocatalysts.

To overcome the problem of element segregation in high entropy alloys and prepare uniform high entropy alloy coatings, FeCoCrNiMox composite powders were prepared by mechanical alloying technique, and it was prepared into high entropy alloy coatings with FCC phase by plasma spraying. The microstructure and phase composition of the coating were characterized by SEM, TEM, and X-ray diffraction. The coating’s hardness, elastic modulus, and fracture toughness were tested and the corrosion resistance was analyzed in simulated seawater. The results show that the hardness of the coating is 606.15 HV, the modulus of elasticity is 128.42 GPa and the fracture toughness is 43.98 MPa•m1/2. The corrosion potential of the coating in 3.5 wt.% NaCl solution is -0.49 V and the corrosion current density is 1.2×10-6A/〖cm〗^2. The electrochemical system consists of three parts: electrolyte, adsorption film and metallic oxide film produced during immerse, and FeCoNiCrMo high-entropy alloy coating. Over increasingly long periods, the corrosion reaction rate increases first and then decreases, the corrosion product film composed of metal oxides reaches a dynamic balance between formation and dissolution, and the internal reaction of the coating slows down.

With the continuous rise of the disposal volume for spent lithium-ion batteries (LIBs), properly recycling spent LIBs has become essential for advancing the circular economy. This study presents a systematic analysis of the chlorination-roasting kinetics and proposes a new two-step chlorination-roasting process for recycling lithium-ion battery cathode materials, integrating thermodynamics. The activation energy for the chloride reaction was determined to be 88.41 kJ/mol based on TG-DTG data using model-free, model-fitting, and Z(α) functions. The results indicated that the reaction was dominated by the First order (F1) model when the conversion rate was below 0.5 and shifted the Second order (F2) model when the conversion rate exceeded 0.5. The effects of roasting temperature, roasting time, and the mass ratio of NH4Cl to LiCoO2 were thoroughly investigated to determine the optimal conditions. Under the optimal parameters of 400°C for 20 minutes with a mass ratio of 3:1 for NH4Cl and LiCoO2, the leaching efficiency of Li and Co reached 99.43% and 99.05%, respectively. Analysis of the roasted products revealed that valuable metals in LiCoO2 transformed into CoCl2 and LiCl. Furthermore, to elucidate the reaction mechanism, providing insights into establishing a novel low-temperature chlorination roasting technology based on a crystal structure perspective. This technology can potentially guide the development of low-energy consumption, low-secondary pollution, high-recovery efficiency, and high-added value processes for LIB recycling.

In this work, multi-stage heat treatment involving quenching (Q), lamellarizing (L), and tempering (T) is applied in marine 10Ni5CrMoV steel to study the microstructure and mechanical properties by multi-scale characterizations, kinetics of reverse austenite transformation, strain hardening behavior, and toughening mechanism are further investigated. The specimens treated by lamellarizing process possess low yield strength but high toughness, especially cryogenic toughness. Introducing lamellarizing process leads to the film-like reversed austenite develops at martensite block and lath boundaries, which refines the martensite structure, and possess the lower equivalent grain size. Kinetic analysis of austenite reversion based on JMAK model shows that the isothermal transformation is dominated by the growth of reversed austenite, and there is a peak temperature (750°C) which makes the transformation of reversed austenite reach the maximum. The strain hardening behavior based on the modified Crussad-Jaoul analysis is indicated that reversed austenite obtained by lamellarizing process reduce the proportion of martensite, whereas produce a significant effect to hinder the propagation of cracks via martensitic transformation during the deformation, which are responsible for the QLT specimens exhibit high machinability and low yield strength. The ductile-brittle transition temperature of QLT specimens is decreased from -116°C to -130°C due to the low equivalent grain size and reversed austenite, which increase the cleavage force required for the propagation of cracks, and absorb the energy of external load, respectively. This work provides an idea to improve the cryogenic toughness of marine 10Ni5CrMoV steel, and lays a theoretical foundation for the industrial application and comprehensive performance improvement.

Different types of gases need to escape through the top of the mold during the continuous casting process of high-Mn high-Al steels. The behavior of bubbles passing through the liquid slag is the restrictive link, which is related to the viscosity. Compared with two-dimensional surface observation, three-dimensional analysis is more intuitive, accurate and comprehensive. The spatial distribution and three-dimensional morphological of residual bubbles in mold flux under different basicity, different temperature and different holding time were obtained by three-dimensional X-ray microscope in this paper. The results indicate that when the basicity increases from 0.52 to 1.03, the temperature increases from 1423 K to 1573 K, the holding time increases from 10 s to 30 s, the mean feret diameter of the bubbles solidified in the mold flux gradually decreases. Increasing the basicity and temperature will decrease the viscosity of the mold flux and increase the bubble floating rate, increasing the holding time will increase the bubble floating distance, both leading to an increase in the removal rate of bubbles especially for the large. The findings of bubbles escape behavior provide guidance for the research of functions of low basicity mold flux for high-Mn and high-Al steel.

The ternary lithium-ion batteries (LIBs), widely used in new energy vehicles and electronic products, is known for its high energy density, wide operating temperature range, and excellent cycling performance. With the rapid development of the battery industry, the recycling of spent LIBs, due to their economic value and environmental concerns, has become a hot topic. To date, there is a wealth of literature on the recycling of spent LIBs, being designed to provide an efficient, economical, and environmentally friendly method for battery recycling. This article examines the latest developments in various technologies for recycling spent LIBs in both research and practical production, including pretreatment, pyrometallurgy, hydrometallurgy, pyro-hydrometallurgy, and direct regeneration. Suggestions are made for addressing challenges based on the benefits and disadvantages of each method. Finally, through a comparison of the feasibility and economic benefits of various technologies, the challenges faced by battery recycling are summarized, and future development directions are proposed.

Microstructures determine mechanical properties of steels, but in actual steel product process it is difficult to accurately control the microstructure to meet the requirements. General microstructure characterization methods are time consuming and results are not representative for overall quality level as only a fraction of steel sample was selected to be examined. In this paper, a macro and micro coupled 3D model was developed for non-destructively characterization of steel microstructures. For electromagnetic signals analysis, the relative permeability value computed by the micro cellular model can be used in the macro electromagnetic sensor model. The effects of different microstructure components on the relative permeability of duplex stainless steel (grain size, phase fraction and phase distribution) were discussed. The output inductance of an electromagnetic sensor was determined by relative permeability values and can be validated experimentally. The findings indicate that the inductance value of an electromagnetic sensor at low frequency can distinguish different microstructures. This method can be applied to real-time on-line characterize steel microstructures in process of steel rolling.

This study aims to investigate mechanical properties and failure mechanisms of layered rock with rough joint surfaces under direct shear loading. Cubic layered samples with dimensions of 100 × 100 × 100 mm were casted using rock-like materials, with anisotropic angle (α) and joint roughness coefficient (JRC) ranging from 15° to 75° and 2 ~ 20, respectively. The direct shear tests were conducted under the application of initial normal stress (σn) ranging from 1 ~ 4 MPa. The test results indicate significant differences in mechanical properties, acoustic emission (AE) responses, maximum principal strain fields, and ultimate failure modes of layered samples under different test conditions. The peak stress increases with the increasing α and achieves a maximum value at α = 60° or 75°. As σn increases, the peak stress shows an increasing trend, with correlation coefficients R² ranging from 0.918 to 0.995 for the linear least squares fitting. As JRC increases from 2 ~ 4 to 18 ~ 20, the cohesion increases by 86.32% when α = 15°, while the cohesion decreases by 27.93% when α = 75°. The differences in roughness characteristics of shear failure surface induced by α result in anisotropic post-peak AE responses, which is characterized by active AE signals when α is small and quiet AE signals for a large α. For a given JRC = 6 ~ 8 and σn = 1 MPa, as α increases, the accumulative AE counts increase by 224.31% (α increased from 15° to 60°), and then decrease by 14.68% (α increased from 60° to 75°). The shear failure surface is formed along the weak interlayer when α = 15° and penetrates the layered matrix when α = 60°. When α = 15°, as σn increases, the adjacent weak interlayer induces a change in the direction of tensile cracks propagation, resulting in a stepped pattern of cracks distribution. The increase in JRC intensifies roughness characteristics of shear failure surface for a small α, however, it is not pronounced for a large α. The findings will contribute to a better understanding of the mechanical responses and failure mechanisms of the layered rocks subjected to shear loads.

Transition metal sulfides have great potential as anode materials for sodium-ion batteries (SIBs) due to their high theoretical specific capacities. However, the inferior intrinsic conductivity and large volume variation during sodiation-desodiation processes seriously affect its high-rate and long-cycle performance, unbeneficial for the application as fast-charging and long-cycling SIBs anode. Herein, the three-dimensional porous Cu1.81S/nitrogen-doped carbon frameworks (Cu1.81S/NC) are synthesized by the simple and facile sol-gel and annealing processes, which can accommodate the volumetric expansion of Cu1.81S nanoparticles and accelerate the transmission of ions and electrons during Na+ insertion/extraction processes, exhibiting the excellent rate capability (250.6 mAh g-1 at 20 A g-1) and outstanding cycling stability (70% capacity retention for 6000 cycles at 10 A g-1) for SIBs. Moreover, the Na-ion full cells coupled with Na3V2(PO4)3/C cathode also demonstrate the satisfactory reversible specific capacity of 330.5 mAh g-1 at 5 A g-1 and long-cycle performance with the 86.9% capacity retention at 2.0 A g-1 after 750 cycles. This work proposes a promising way for the conversion-based metal sulfides for the applications as fast-charging sodium-ion battery anode.

In recent years, medium entropy alloys have become a research hotspot due to their excellent physical and chemical performances. By controlling reasonable elemental composition and processing parameters, the medium entropy alloys can exhibit similar properties to high entropy alloys and have lower preparation costs. In this paper, a FeCoNi medium entropy alloy precursor was prepared via sol-gel and co-precipitation methods, respectively, and FeCoNi medium entropy alloys were prepared by carbothermal and hydrogen reduction. The phases and magnetic properties of FeCoNi medium entropy alloy were investigated. Results showed that the decompose temperature of the precursor prepared by sol-gel and co-precipitation methods was 369 °C and 834 °C, respectively. FeCoNi medium entropy alloy was produced by carbothermal and hydrogen reduction at 1500 °C. Some carbon was detected in the FeCoNi medium entropy alloy prepared by carbothermal reduction. The FeCoNi medium entropy alloy prepared by hydrogen reduction had uniform composition, and showed a relative high purity. Moreover, hydrogen reduction product exhibited a higher saturation magnetization and lower coercivity.

High-entropy design is attracting growing interest as it offers unique structures and unprecedented application potential for materials. In this article, a novel high-entropy ferrite (CoNi)x/2(CuZnAl)(1-x)/3Fe2O4 (x = 0.25, 0.34, 0.40, 0.50) with a single spinel phase of space group Fd-3m was successfully developed by the solid-state reaction method. By tuning the Co-Ni content, the magnetic properties of the material, especially the coercivity, changed regularly, and the microwave absorption properties were improved. In particular, the effective absorption bandwidth of the material increased from 4.8 GHz to 7.2 GHz, and the matched thickness decreased from 3.9 mm to 2.3 mm, while the minimum reflection loss remained below -20 dB. This study provides a practical method for modifying the properties of ferrites used to absorb electromagnetic waves.

High pressure die casting (HPDC) AlSi10MnMg alloy castings are widely used in the automobile industry. Mg can enhance the strength of the alloy with the sacrifice of the ductility. Heat treatment was generally adopted to resolve this drawback. With the development of large integrated die-casting parts, non-heat treatment Al alloys are strongly desired. In addition, the externally solidified crystals (ESCs) are often found in HPDC, which are detrimental to the mechanical properties of castings. In order to achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy, AlSi9Mn alloy is used as matrix with the introduction of Zr, Ti, Nb and Ce elements. Their influences on the ESCs and mechanical properties were systematically investigated by combining three-dimensional reconstruction and thermodynamic simulation. Our results reveal that the addition of Ti element induced the increase of ESCs size and porosity. The following introduction of Nb could refine ESCs and decrease porosity. Meanwhile, the large-sized Al3(Zr, Ti) phases formed and degraded the mechanical properties. It was further confirmed that the subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.

The pervasive use of 5th generation mobile communication technology is driving electromagnetic wave (EW) absorbents towards high performances. The construction of heterointerfaces is crucial to the improvement of absorption ability. Herein, a series of ultralight composites with rational heterointerfaces (Co/ZnO@N-doped C/layer-stacked C, MSC) are fabricated by calcination with rational construction of sugarcane and CoZn-ZIFs. The components and structures of as-prepared composites were investigated, and their electromagnetic parameters could be adjusted by the content of CoZn-ZIFs. All the composites possess good EW absorption performances, especially for MSC-3. Its optimal minimum reflection loss and effective absorption band can reach to -42 dB and 7.28 GHz at the thickness of just 1.6 mm with 20 wt% filler loading. The excellent performances are attributed to the synergistic effect of dielectric loss stemming from the multiple heterointerfaces and magnetic loss induced by magnetic single Co. And the sugarcane-derived layer-stacked carbon and formed consecutive conductive networks and could further dissipate the electromagnetic energy through multiple reflection and conduction loss. Moreover, the simulated radar cross section (RCS) technology manifests that MSC-3 possesses outstanding EW attenuation capacity under realistic far-field conditions. This study provides a strategy for building efficient absorbents based on biomass.

The utilization of iron coke provides a green pathway for low-carbon ironmaking. To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification, the effect of iron ore on the microstructure of iron coke was investigated. Furthermore, a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method. The findings indicate that compared to coke, iron coke exhibits an augmentation in micropores and specific surface area, and the micropores further extend and interconnect. This provides more adsorption sites for CO2 molecules during the gasification process, resulting in a reduction in the initial gasification temperature of iron coke. Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke. The metallic iron reduced from iron ore is embedded in the carbon matrix, reducing the orderliness of the carbon structure, which is primarily responsible for the heightened reactivity of the carbon atoms. The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure. Moreover, as the proportion of iron ore increases, the activation energy for the carbon gasification gradually decreases, from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15%.

Deriving PC materials through biomass sources is a sustainable, ubiquitous, and low-cost method, which comes with many desired features, such as hierarchical texture, periodic pattern, and some unique nanoarchitecture. Herein, a new strategy of using Peanuts as Honeycomb-like carbon precursors and Fe3O4 as magnetic precursor to prepare excellent performance absorbing materials. During the carbonization process, the Peanut-shell changes into the interconnected Honeycomb-like porous carbon materials, and the precursor ferric salt converts into magnetic Fe3O4 nanoparticles. As a result, the obtained MA materials P-C-800@Fe3O4(1:0.5) exhibit outstanding MA performance. When the ration reaches at 4:6, it displays the minimum reflection Loss(RL) of -59.2 dB at 3.36mm, and the effective absorption bandwidth (RL<-10 dB) can reach 7.5 GHz(from 9.5 to 17 GHz) at 2.0 mm. The honeycomb-like composite materials, interfacial polarization, synergistic enhancement between dielectric loss and magnetic loss, multiple reflections, and scatterings make enhancement to the MA capability. This paper might provide an effective and facile strategy to prepare magnetic honeycomb-like porous carbon derived from biomass for MA applications.

The element distribution and microstructure near surface of a high-Mn high-Al austenitic low-density steel were investigated after isothermal holding at temperatures ranging from 900°C to 1200°C in different atmospheres, including air, N2 and N2 + CO2 mixed atmospheres. The results show that no ferrite formed near the surface of the experimental steel during isothermal holding at 900°C and 1000°C in air, while ferrite formed near the surface when the isothermal temperature reached 1100°C and 1200°C. The fraction of ferrite was larger at 1200°C because more C and Mn diffused to the surface and exuded from steel, which then reacted with N and O to form oxidation products. The thickness of compound scale increased due to the larger diffusion rate at a higher temperature. In addition, after isothermal holding at 1100°C in N2, Al content near the surface reduced slightly, while the contents of C and Mn did not change. Therefore, no ferrite formed near the surface. However, the contents of C and Al near the surface reduced after holding at 1100°C in N2 + CO2 mixed atmosphere, resulting in a small amount of ferrite. The thickness of compound scale was found to be the thickest in N2, followed by N2 + CO2 mixed atmosphere, and the thinnest in air. Overall, the element loss and ferrite fraction were the largest after holding in air at the same temperature. The differences in element loss and ferrite fraction were small in N2 and N2 + CO2 mixed atmospheres, but the compound scale formed in N2 was significantly thicker. Based on these results, the N2 + CO2 mixed atmosphere is the most ideal heating atmosphere for industrial production of high-Mn high-Al austenitic low-density steel.

The atmospheric corrosion monitoring (ACM) technique has been widely employed to track the real-time corrosion behavior of metal materials. However, limited studies have employed ACM to monitor the corrosion protection properties of organic coatings. This study focused on comparing a bare epoxy coating with one containing zinc phosphate corrosion inhibitors, both applied on ACM sensors, to observe their corrosion protection properties over time. The coatings underwent artificial damage via scratches and were then exposed to immersion as well as alternating dry and wet environments. This allowed for monitoring the galvanic corrosion currents in real-time. Throughout the corrosion tests, the zinc phosphate/epoxy coating displayed significantly lower ACM currents compared to the blank epoxy coating. The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis. This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings. Compared with the blank epoxy coating, the much decreased ACM current values observed on the zinc phosphate/epoxy coating confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.

 Herein, ferrocene and a nitrogen heterocyclic compound (either melamine or imidazole) were hyper-crosslinked via an external crosslinker through a straightforward Friedel–Crafts reaction, leading to the formation of nitrogen-containing hyper-crosslinked ferrocene polymer precursors (HCPs). These precursors were subsequently carbonized to produce iron–nitrogen-doped porous carbon absorbers (Fe-NPCs). The Fe-NPCs feature a porous structure comprising aggregated nanotubes and nanospheres, with porosity that can be modulated by adjusting the iron and nitrogen content to optimize impedance matching. The use of hyper-crosslinked ferrocenes in constructing porous carbon ensures the uniform distribution of Fe-NxC, N dipoles, and α-Fe within the carbon matrix, providing the absorber with numerous polarization sites and a conductive network. The specially designed Fe-NPC-M2 absorbers exhibit satisfactory electromagnetic wave absorption performance, with a minimum reflection loss of −55.3 dB at 2.5 mm and an effective absorption bandwidth of 6.00 GHz at 2.0 mm. This research introduces a novel method for developing highly efficient carbon-based absorbing agents by utilizing hyper-crosslinked polymers as precursors.

Electromagnetic interference is of urgent concern in contemporary society, necessitating the swift advancement of substances with exceptional capabilities in absorbing electromagnetic waves. In this work, a direct hydrothermal method was utilized to create CoFe2O4/residual carbon from coal gasification fine slag (CFO/RC) composites. These composites encompass various mechanisms for microwave absorption, including conductive loss, natural resonance, interfacial dipole polarization, and magnetic flux loss. Consequently, compared with pure residual carbon materials this composite offers superior capabilities in microwave absorption. At 7.76 GHz, the CFO/RC-2 composite achieves an impressive minimum reflection loss (RLmin) of −43.99 dB with a thickness of 2.44 mm. Moreover, CFO/RC-3 demonstrates an effective absorption bandwidth (EAB) of up to 4.16 GHz, accompanied by a thickness of 1.18 mm. This study revealed the remarkable ability of the composite to diminish electromagnetic waves, providing a new method for generating microwave absorbing materials of superior quality.

Biopolymers have been widely used as triboelectric materials in constructing self-powered sensing system, whereas the annihilation of triboelectric charges at high temperatures restricted the output signals as well as the sensitivity of assembled sensors. Herein, a novel chitosan/montmorillonite/lignin (CML) composite film was designed and employed as the tribopositive layers in assembling self-powered sensing system under hot conditions (25-70oC). Originating from the strong intermolecular interaction between biopolymers and nanofillers, the dense contact surface restrained the volatilization of induced electrons. The optimized CML-TENG delivered the highest open circuit voltage (Voc) of 262 V and a maximum instantaneous output power of 429 mW/m2. Furthermore, the best CM5L3-TENG retained 66% of its initial Voc at 70℃, which is much higher than the pristine chitosan film (39%). Our work provides a new strategy to suppress the annihilation of triboelectric charges at high temperatures, boosting the development of self-powered sensing device under hot conditions.

In order to conduct more extensive research on the application of ionic liquids (ILs) as collectors in minerals flotation, ethanol (EtOH) was used as a solvent to dissolve hydrophobic ILs to simplify the reagent regime. Some interesting phenomena were observed that EtOH caused different effects on the flotation efficiency of two ILs with similar structures. When EtOH was used to dissolve 1-Dodecyl-3-methylimidazolium chloride (C12[mim]Cl), and C12[mim]Cl as collector for pure quartz flotation tests at the concentration of 1*10-5mol*L-1, quartz recovery increased from 23.77% to 77.91% compared with ILs dissolved in water. However, quartz recovery of 1-Dodecyl-3-methylimidazolium hexafluorophosphate (C12[mim]PF6) decreased from 60.45% to 24.52% in the same cases. the EtOH concentration tests under 1*10-5mol*L-1 ILs and the ILs concentration tests under 2% EtOH confirmed this. After being affected by EtOH, the mixed ore flotation tests of quartz and hematite showed a decrease in the hematite concentrate grade and recovery for C12[mim]Cl collector, while the hematite concentrate grade and recovery for C12[mim]PF6 collector both increased. Based on these interesting differences and observation in flotation tests, the two-phase bubble observation tests were carried out and it showed that EtOH promoted foam height of two ILs during aeration but accelerated static froth defoaming after aeration stopped, and the foam of C12[mim]PF6 defoaming more quickly. Through the discussion of flotation tests and foam observation, an attempt was made to explain the reasons and mechanisms of various differences phenomenon using the dynamic surface tension effect and solvation effect result from EtOH. The solvation effect was verified by IR, XPS and Zeta potential tests. It can be assumed that although EtOH has a negative effect on the adsorption of ILs on the ore surface during the flotation process, it has application reference value for the inhibition of foam merging during the flotation aeration process and the acceleration of the defoaming of static foam. These effects induced a stronger secondary enrichment in the mixed ore flotation of C12[mim]PF6 collector, so that C12[mim]PF6 obtained good mixed ore separation under the condition of no any inhibitor.

This study aimed to investigate the impact of varying contents of pyrite on copper in the presence of different regrinding conditions, which were altered by using two types of grinding media, iron and ceramic balls, followed by flotation in the cleaner stage. It was found that the flotation performance of rougher copper concentrate can be improved by changing the regrinding conditions based on the content of pyrite. SEM-EDS (scanning electron microscope), X-ray spectrometer, EDTA extraction and XPS (X-ray photoelectron spectroscopy) studies illustrated that when the pyrite content was high, using iron media to regrind was beneficial to promote the generation of hydrophilic FeOOH on the surface of pyrite and improve copper grade. While using ceramic media for low pyrite content would avoid too much FeOOH covering the surface of chalcopyrite. Electrochemical studies further showed that the galvanic corrosion current of chalcopyrite-pyrite increased with the addition of pyrite and became stronger with the participation of iron media.

Lithium metal batteries (LMBs) are promising high-energy-density battery systems due to their high specific capacity. However, the non-uniform plating of lithium (Li) and the collapse of the solid electrolyte interphase (SEI) during cycling gives rise to the risk of dendrite growth, which could penetrate the separator and bring the hazards of short-circuit. The availability of stable SEI is a prerequisite for the long-term operation of the batteries to overcome these challenges. Fluorinate-rich SEI has attracted much attention due to its effective passivation of electrodes, regulation of Li deposition and inhibition of electrolyte corrosion. This paper reviews the research on optimizing the preparation of LiF passivation interfaces for the protection of lithium metal anodes, and four types of compositions introduced in fluorinated SEI to synergistically enhance the comprehensive performance of SEI. By emphasizing the importance of interphasial structures, this review offers comprehensive guidance for the design and development of LMBs.

Martensite is a very important microstructure in ultra-high-strength steel materials, and enhancing the strength of martensitic steels often involves the introduction of precipitated phases within the martensitic matrix. Despite considerable research efforts have been devoted in this area, a systematic summary of these advancements is lacking. In this review, some prevalent precipitates observed in ultra-high strength martensitic steels are summarized, focusing primarily on carbides (e.g., MC, M2C, M3C) and intermetallic compounds (e.g., NiAl, Ni3X, Fe2Mo). The precipitation-strengthening effect of these precipitates on ultra-high strength martensitic steels is discussed from the aspects of heat treatment processes, the microstructure of precipitate-strengthened martensite matrix, and mechanical performance. Finally, a perspective on the development of precipitated phase strengthened martensitic steel is provided, aiming to contribute to the advancement of ultra-high strength martensitic steel. This review not only highlights significant findings but also underscores ongoing challenges and opportunities within the field of ultra-high strength martensitic steel development.

Calcium ferrite is recognized as a potential green and efficient functional material due to its advantages of magnetism, electrochemistry, catalysis, and biocompatibility in the fields of materials chemistry, environmental engineering, and biomedicine. Therefore, it is essential to systematically summarize the obtained research results and analyze new perspectives on calcium ferrite and its composite materials. Based on the presented studies on calcium ferrite and its composite materials, the types and structures of the crystal are summarized. In addition, the current application technologies and theoretical mechanisms with various properties in different fields are elucidated. Moreover, the various preparation methods of it and its composites are elaborated in detail. Above all, the advantages and disadvantages of the synthesis methods of calcium ferrite and its composite materials are discussed, and the main problems existing and the challenges faced in practical production in the future are pointed out. Furthermore, the key future research directions of calcium ferrite and its composite materials have prospected from the potential application technologies to provide references for its synthesis and efficient utilization.

As a mathematical analysis method, fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties. It has been applied to shape characterization at various scales and dimensions in metal materials. Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics of surface and interfaces and properties in the study of metal materials. However, fractal analysis can quantitatively describe the shape characteristics of metal materials and then establish the quantitative relationship between these shape characteristics and various properties of metal materials. From the perspective of two-dimensional planes and three-dimensional curved surfaces, this paper reviews the current research status of fractal analysis in metal precipitate interfaces, metal grain boundary interfaces, metal deposited film surfaces, metal fracture surfaces, metal machined surfaces and metal wear surfaces. The relationship between the fractal dimension of the surface and interface and the properties of metal materials is summarized. Starting from three perspectives of fractal analysis, which are the research scopes, image acquisition methods and calculation methods, this paper points out the direction of research on fractal analysis of surface and interfaces of metal materials that need to be developed. It is believed that revealing the deep mechanism between the fractal dimension of the surface and interface and the properties of metal materials will be the key research direction of fractal analysis of metal materials in the future.

The urgent need for integrated molding and sintering across various industries has inspired the development of additive manufacturing (AM) ceramics. Among the different AM technologies, direct laser additive manufacturing (DLAM) stands out as a group of highly promising technology for flexibly manufacturing ceramics without molds and adhesives in a single step. Over the last decade, significant and encouraging progress has been accomplished in DLAM of high-performance ceramics, including Al2O3, ZrO2, Al2O3/ZrO2, SiC, and others. However, high-performance ceramics directly fabricated by DLAM face challenges such as formation of pores and cracks and resultant low mechanical properties, hindering their practical application in high-end equipment. Further improvements are necessary before they can be widely adopted. Methods such as field-assisted techniques and post-processing can be employed to address these challenges, but a more systematic review is needed. This work aims to critically review the advancements in selective laser sintering/melting (SLS/SLM) and laser directed energy deposition (LDED) for various ceramic material systems. Additionally, it provides an overview of the current challenges, future research opportunities, and potential applications associated with DLAM of high-performance ceramics.

Safe emplacement of high-level nuclear waste (HLNW) arising from the utilization of nuclear power is a frequently encountered and considerably challenging issue. The widely accepted and feasible approach for the permanent disposal of HLNW involves housing it in a corrosion-resistant container and subsequently burying it deep in a geologic repository. The focus lies on ensuring the durability and integrity of the container in this process. This paper introduces various techniques and strategies employed in controlling the corrosion of used fuel containers (UFCs) using copper (Cu) as a corrosion barrier in the context of deep geological disposal. Overall, these corrosion prevention techniques and methods have been effectively implemented and employed to successfully mitigate the corrosion challenges encountered during the permanent disposal of Cu containers (e.g., corrosion mechanisms, corrosion parameters) in deep geologic repositories. The primary objective of this review is to provide an extensive examination of the alteration in the corrosion environment encountered by the UFCs when subjected to deep geologic repository conditions and focusing on addressing the potential corrosion scenarios.

In the realm of proton exchange membrane fuel cells (PEMFCs), the bipolar plates (BPs) are indispensable and serve pivotal roles in distributing reactant gases, collecting current, facilitating product water removal, and cooling the stack. Metal BPs, characterized by outstanding manufacturability, cost-effectiveness, higher power density, and mechanical strength, are emerging as viable alternatives to traditional graphite BPs. The foremost challenge for metal BPs lies in enhancing their corrosion resistance and conductivity under acidic conditions, necessitating the application of various coatings on their surfaces to ensure superior performance. This review summarizes and compares recent advancements in the research of eight distinct types of coatings for BPs in PEMFCs, including noble metal, carbide, nitride, and a-C + metal/metal compound composite coatings. The various challenges encountered in the manufacturing and future application of these coatings are also delineated.

The rich resources and unique environment of moon position it as the prime candidate for human development and the utilization of extraterrestrial resources. Oxygen plays a vital role in supporting human life on the moon, with lunar regolith serving as a highly oxygen-rich polymetallic oxide that can be processed using existing metallurgical techniques to extract oxygen and metals. Furthermore, the ample reserves of water ice on the moon offer an additional avenue for oxygen production. This paper offers a detailed overview of the leading technologies poised to achieve in-situ oxygen production on the moon, drawing from an analysis of lunar resources and environmental conditions. It delves into the principles, processes, advantages, and drawbacks of water ice electrolysis, two-step oxygen production from lunar regolith, and one-step oxygen production from lunar regolith. The two-step methods involve hydrogen reduction, carbothermal reduction, and hydrometallurgy, while the one-step methods encompass fluorination/chlorination, high-temperature decomposition, molten salt electrolysis, and molten regolith electrolysis (MOE). Following a thorough comparison considering raw materials, equipment, technology, and economic viability, MOE emerges as the most promising approach for future lunar in-situ oxygen production. Considering the high-temperature corrosion characteristics of molten lunar regolith, as well as the environmental characteristics of low gravity on the moon, the development of inexpensive and stable inert anodes and the development of electrolysis devices that can easily collect oxygen are considered key breakthroughs in promoting MOE technology on the moon. This review holds substantial theoretical importance in enhancing our understanding of lunar in-situ oxygen production technology and the forthcoming lunar exploration initiatives.

The photocatalytic activities of catalysts depend on energy harvesting ability and the separation/transport of photogenerated carriers. The surface plasmon resonance (SPR) of noble metal nanoparticles (e.g., Cu, Au, Pd etc.) can be adjusted in the entire visible region via varying the nanocomponents of the material to attain enhanced light absorption capacity of graphitic carbon nitride (g-C3N4) based composites. With the SPR of noble metals been able to enhance the local electromagnetic field and improve the interband transition as well as the resonant energy transfer occurred from the plasmonic dipoles to electron-hole pairs via near-field electromagnetic interactions, noble metals have been quite popular nanocomponents materials in the case of g-C3N4 modification for the applications of CO2 photoreduction and water splitting. Herein, recent key advances in noble metals (either in single atom, cluster, or nanoparticle forms) and inorganic/organic nanocomponents incorporated g-C3N4 nanosheets based composite photocatalysts with improved photoinduced charge mobility are systematically discussed, particularly, the significant applications of these photocatalysts in CO2 photo-conversion and H2 production. Issues related to the different types of multi-nanocomponent heterostructures (involving Schottky junctions, Z-/S-scheme heterostructures, composed of noble metals and additional semiconductor nanocomponents) as well as the adjustment of dimensionality of the heterostructures (by incorporating noble metal nanoplates on g-C3N4 forming 2D/2D heterostructures) are also discussed. The current prospects and possible challenges of the noble metal (e.g., Au, Pt, Pd, and Cu) incorporated g-C3N4 composite photocatalysts, particularly in water splitting, CO2 reduction, pollution degradation, and chemical conversion applications are summarized.

Interface modulation is an important pathway for high-efficiency electromagnetic wave absorption. Herein, tailored interfaces between Fe3O4 particles and the hexagonal-YFeO3 (h-YFeO3) framework were constructed via facile self-assembly, resulting in enhanced dielectric and magnetic loss synergy via interfacial electron rearrangement at the heterojunction. Experimental results and density function theory (DFT) simulations demonstrate a transition in electrical properties from a half-metallic monophase to metallic Fe3O4/h-YFeO3 composites, emphasizing the advantageous effect of hetero-interface formation. The transformation of electron behavior demonstrates a redistribution of electrons at the Fe3O4−h-YFeO3 heterojunction, leading to a localized electron accumulation around the Y-O-Fe band bridge, consequently yielding enhanced polarization. A minimum reflection loss of -34.0 dB can be achieved at 12.0 GHz at 2.0 mm thickness with an effective bandwidth of 3.3 GHz due to the abundant interfaces, enhanced polarization, and rational impedance. Thus, the synergistic effects endow the Fe3O4/h-YFeO3 composites with high-performance and tunable functional properties for efficient electromagnetic absorption.