The development of stretchable conductors with high deformation, conductivity, and thermal conductivity using liquid metal (LM) has sparked widespread discussion in the fields of flexible electronics, electromagnetic interference (EMI),and multifunctional materials. However, directly coating LMs on soft polymer substrates to form desirable shielding materials is still a challenge due to their huge surface tension and weak wettability. In this paper, A gallium-based composite material in paste form called LMP is prepared by fabricating mixture with Ga and diamond non-metallic particles through employing ultrasonic fragmentation. The resulting LMP exhibits both soft and hard properties at various temperatures, allowing it to be molded into specific shapes according to the application needs. This composite can be easily coated onto polymer substrates, such as thermoplastic polyurethane elastomer (TPU), to create the liquid metal composite putty film (LMP-TPU).LMP-TPU exhibits an impressive shape deformation capacity of 1100%, demonstrating exceptional tensile properties and achieving electromagnetic shielding effectiveness of up to 52 dB. Furthermore, it retains an ultra-high conductivity of 20000 S/m, even under a strain of 600%. This further makes it a highly competitive new multifunctional material.

Electrode materials that rely on conversion reactions for lithium-ion batteries (LIBs) are known for their higher energy densities. However, a key issue in their design is to bolster their stability and to minimize the volume variations that occur during lithiation and delithiation. Herein, an effective strategy has been devised to fulfill the fully reversible conversion reaction for lithium storage in CoMoO4 by hybridizing CoMoO3. The CoMoO3/CoMoO4 with a nanorod structure was synthesized via one-step annealing treatment after a solvothermal process. In such a structure, CoMoO3/CoMoO4 nanorod can significantly boost their mechanical robustness and offer ample space to counteract volume fluctuations throughout successive cycles, owing to the cooperative interaction between CoMoO3 and CoMoO4. The CoMoO3/CoMoO4 exhibits a superior lithium-storage capacity (919.6 mAh/g at 0.1 A/g after cycling for 200) and cycling stability (683.4 mAh/g after at 1 A/g after cycling for 600). The CoMoO3/CoMoO4 show high potential as an anode material for LIBs.

The production processes for Si and FeSi have traditionally been considered slag-free. However, recent excavations have revealed significant accumulation of CaO-SiO2-Al2O3 slag within the furnaces. This accumulation can obstruct the flow of materials and gases, resulting in lower metal yield and higher energy consumption. The main objective of the current work is to enhance our understanding of slag formation during Si and FeSi production. We investigate slag formation through the dissolution of limestone and iron oxide in quartz and condensate, focusing on the reactions between these materials at a gram scale. Our findings indicate that most slag reaches equilibrium relatively quickly at temperatures starting from 1673 K. Notably, slag formation starts at lower temperature when the iron source (1573 K) is present compared to when only CaO is involved (1673 K). The minor elements tend to accumulate at quartz grain boundaries prior to slag formation. Furthermore, the slag produced from condensate contains less SiO2 than that generated from quartz with limestone. The type of quartz source and SiO2 phase appears to have little influence on slag formation. Good wettability is a significant factor in reaction between quartz and slag. FactSage calculations indicates that the viscosity of the slag ranges from 0.2 to 144 Poise under furnace conditions, comparable to the viscosity of honey or motor oil at room temperature.

The current study investigates the hot deformation behavior of Al-12Ce-0.4Sc alloy through an isothermal hot compression test in the range of 300-450°C/0.001-1 s^(-1). The flow curves exhibit typical dynamic recovery (DRV) and slight flow softening behavior. Additionally, an-overlapping of flow curves attributed to the dynamic strain aging (DSA) phenomenon in the range of 400-450℃/0.01-0.1 s^(-1). The two different constitutive models were developed using the experimental data for the hot deformation: (i) strain-compensated Arrhenius model (Method I), and (ii) logistic regression model (Method II). The average stress exponent (n) and apparent activation energy (Q) were determined to be 14.25 and 209.58 kJ 〖mol〗^(-1), respectively. The hot working processing map shows the optimal processing condition at 400°C/1 s^(-1) with a maximum power dissipation efficiency of 22%. The stable and instable domains indicated by the processing map were correlated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD) characterization techniques. Instability domains were primarily associated with pro-eutectic Al11Ce3 intermetallic fracture and interfacial cracks between the α-Al and the pro-eutectic Al11Ce3.

The precise identification of quartz minerals is crucial in mineralogy and geology due to their widespread occurrence and industrial significance. Traditional methods of quartz identification in thin sections are labor-intensive and require significant expertise, often complicated by the coexistence of other minerals. This study presents a novel approach leveraging deep learning techniques combined with hyperspectral imaging to automate the identification process of quartz minerals. Utilizing four advanced deep learning models—PSPNet, U-Net, FPN, and LinkNet—this method demonstrates significant advancements in efficiency and accuracy. Among these, PSPNet exhibited superior performance, achieving the highest Intersection over Union (IoU) scores and demonstrating exceptional reliability in segmenting quartz minerals, even in complex scenarios. The study involved a comprehensive dataset of 120 thin sections, encompassing 2470 hyperspectral images prepared from 20 rock samples. Expert-reviewed masks were used for model training, ensuring robust segmentation results. This automated approach not only expedites the recognition process but also enhances reliability, providing a valuable tool for geologists and advancing the field of mineralogical analysis.

Low to medium maturity oil shale resources boast substantial reserves, offering promising prospects for in-situ conversion in China. It is of great significance to investigate the evolution of the mechanical properties of reservoir and caprock under in-situ high-temperature and confinement conditions. Compared to conventional mechanical experiments on rock samples after high-temperature treatment, in-situ high-temperature experiments can more accurately characterize the behavior of rocks in practical engineering, thereby providing a more realistic reflection of their mechanical properties. Therefore, an in-situ high temperature triaxial compression testing machine is developed for conducting in-situ compression tests on sandstone under different temperatures (25, 200, 400, 500, and 650℃) and different confining pressures (0, 10, and 20 MPa). Based on the experimental results, the evolution characteristics of compressive strength, peak strain, elastic modulus, Poisson’s ratio, cohesion, and internal friction angle with temperature are deeply analyzed and discussed. It is observed that the mass of sandstone gradually decreases with increasing temperature. The thermal conductivity and thermal diffusivity of sandstone exhibit a linear relationship with temperature. Peak stress decreases with rising temperature and increases with higher confining pressure. Notably, the higher the temperature, the worse the effect of the confining pressure on the peak stress. Additionally, the Poisson’s ratio of sandstone decreases as temperature rises. The internal friction angle also decreases with increasing temperature, with 400°C serving as the threshold temperature. Interestingly, under uniaxial conditions, the damage stress of sandstone is less affected by temperature. The damage stress decreases with increasing temperature when the confining pressure is 10 and 20 MPa. This study enhances our understanding of how the mechanical properties of sandstone strata change under in-situ high-temperature and confinement conditions. It provides valuable references and experimental data that support the development of low to medium maturity oil shale resources.

Tensile deformation and microvoid formation of quenched and tempered SA508 Gr.3 steel are studied by in-situ digital image correlation (DIC) technique and in-situ EBSD measurement. The quenched steel with a mixture of bainite and M-A islands exhibits a high ultimate tensile strength (UTS~795 MPa) and an elongation of about 25%. After tempering, long rod carbides and accumulated carbide particles are formed at the interface of bainite-ferrite subunits and prior austenite grain boundary (PAGB), respectively. UTS of the tempered steel decreases to about 607 MPa, while the total elongation increases to about 33% with a local strain of about 191% at the necked area. In-situ EBSD results show that strain localization in the bainite-ferrite produces lattice rotation and dislocation pileup, thus leading to stress concentration at the discontinuities (such as M-A island and carbides). As a result, the decohesion of PAGB dotted with M-A islands is the dominate microvoid initiation mechanism in the quenched steel, while the microvoids initiate by fracture of long rod carbides and decohesion of PAGB with carbides aggregation in the tempered steel. The fracture surfaces both for quenched and tempered specimens are featured by dimples, indicating the ductile failure mechanism caused by microvoid coalescence.

In the field of broadband metamaterial absorbers, most research efforts have focused on optimizing the resonant layers and designing multi-layer structures, with relatively little attention paid to the dielectric layers themselves. This paper proposes a method of modifying the dielectric layer using carbonyl iron powder, which significantly enhances the electromagnetic wave attenuation capability of the dielectric layer in the X-band for metamaterial absorber. A broadband absorber capable of effectively absorbing electromagnetic waves (RL≤-10dB) over the frequency range of 4.92-18GHz, covering the C, X, and Ku bands, was designed. We analyzed the surface current distribution, power loss distribution, etc. to elucidate the absorption mechanism of the absorber. It was found that the modified dielectric layer accounted for more than 50% of the total loss in the 2-18GHz frequency band, and the effective absorption bandwidth was almost twice that of the unmodified dielectric layer, attributed to the introduction of a new electromagnetic wave loss mechanism by carbonyl iron powder. Meanwhile, the absorber exhibited good angular stability, maintaining at least 80% absorption (RL ≤ -7 dB) in the 6.0-18.0 GHz range even when the incident angle was increased to 60°. The experimental results show that the measured results match the simulation results well, and compared with other methods for broadening the absorption bandwidth, the metamaterial absorber obtained by this method offers several advantages, including wideband absorption, thin profile, and a simple manufacturing process. This approach provides a new and promising direction for the design of broadband absorbers.

Corrosion degradation of organic coatings in tropical marine atmospheric environments leads to substantial economic losses across various industries. The complexity of the dynamic environment, combined with high costs, extended experimental periods, and limited data, has made understanding this process challenging. This study addresses these challenges by investigating the corrosion degradation of damaged organic coatings in a tropical marine environment using an atmospheric corrosion monitoring (ACM) sensor and a random forest (RF) model. A polyurethane coating applied to an Fe/graphite corrosion sensor was intentionally scratched to simulate damage and then exposed to the marine atmosphere for over one year. Environmental and corrosion current data were collected and filtered using Pearson correlation analysis. The RF model identified specific conditions that contribute to accelerated degradation: relative humidity (RH) above 80% and temperatures below 22.5°C, with the risk increasing significantly when RH exceeds 90%. High RH and temperature were found to have a cumulative effect on the degradation of coatings. A high risk of corrosion was observed in the nighttime. The RF model was also used to predict the coating degradation process using environmental data as input parameters, with an accuracy improved by considering the duration of influential environmental ranges.

To study the effects of gangue particle-size gradation on the damage characteristics of cemented backfill, investigation techniques such as uniaxial compression tests, acoustic emission, digital image correlation monitoring, and scanning electron microscopy were used from macroscopic and microscopic perspectives. The peak strength, acoustic emission characteristics, and failure modes of cemented backfills with different gangue size gradations were investigated. The test results indicated that with an increase in the gradation coefficient, the compressive strength of the gangue cemented backfill first increased and then decreased, when the gradation coefficient is 0.5, the maximum compressive strength of the backfill is 4.28 MPa. The acoustic emission counts during the loading of gangue cemented fills with different gradation coefficients passed through three phases: rising, active, and significantly active. Because of the different gangue particle-size gradations under the filler sample, the number of internal pores and cracks, and the distribution of the location of the unequal, causes differences in acoustic emission characteristics at the same stage and differences in the strength of the backfill.

Growing concerns about greenhouse gas emissions from underground mining have heightened scrutiny, making it crucial to implement carbon reduction strategies at every stage, with shotcrete used in tunnel support offering a promising opportunity to reduce emissions.This paper investigates the carbon absorption capacity, mechanical strength, and underlying mechanisms of shotcrete when exposed to varying carbon dioxide (CO2) concentrations during the mine support process. The findings reveal that higher CO2 concentrations during the initial stages of carbonation curing enhance early strength but may impede strength development over time. Specifically, shotcrete samples exposed to 2% CO2 for 14 days exhibited a carbonation rate approximately four times higher than those exposed to 0.03% CO2. A significant carbonation layer formed in the shotcrete, sequestering CO2 as solid carbonates. In practical terms, shotcrete in an underground return air tunnel absorbed 1.1 kg of CO2 per square meter over 14 days, equivalent to treating 33 m3 of contaminated air. Thus, using shotcrete for CO2 curing in return air tunnels can significantly reduce carbon emissions, contributing to greener and more sustainable mining practices..

Strong and ductile Al alloys and their design strategy have long been desired for selective laser melting. This work reports a non-equilibrium partitioning model and the correspondingly designed Al-7.5Mg-0.5Sc-0.3Zr-0.6Si alloy. By considering the non-equilibrium partitioning under high cooling rates in selective laser melting, this model properly quantifies the influence of Mg and Si on hot cracking of aluminum. The designed Al-7.5Mg-0.5Sc-0.3Zr-0.6Si alloy exhibits no hot cracks and a much-improved strength-ductility synergy (the yield strength being 412 ± 8 MPa, the uniform elongation being 15.6 ± 0.6 %) much more superior than that of previously reported Al-Mg-Sc-Zr, Al-Mn, etc. A tensile cracking model is proposed to explore the origin of improved ductility. The non-equilibrium partitioning model and the novel Al-7.5Mg-0.5Sc-0.3Zr-0.6Si offer a good opportunity for producing highly reliable aluminum parts by selective laser melting.

Nanoferrites of the CoMnxFe(2-x)O4 series (x = 0.00, 0.05, 0.10, 0.15, 0.20) were synthesized using the sol-gel auto-combustion approach. Lattice constants were computed within the range of 8.312–8.406 Å, while crystallite sizes were estimated to be 55.20–31.40 nm using the Scherrer method. The different functional groups were found to correlate with different absorption bands using Fourier transform infrared (FTIR) spectroscopy. Five active modes were identified by Raman spectroscopy, revealing vibration modes of O2- ions at both tetrahedral and octahedral locations. The ferromagnetic hysteresis loop was observed in all the synthesized samples, and these are explained by Neel’s model. The ac conductivity decreases with increasing Mn2+ content at the Fe2+ site. Besides, both the dielectric constant and dielectric loss increased with increasing frequency. Moreover, the saturation magnetization (Ms), remnant magnetization (Mr), and coercivity (Hc) all showed declining trends with the increase in Mn2+ doping. The CoMn0.20Fe1.8O4 samples showed Ms ranging from 73.12 to 66.84 emu/g, Mr from 37.77 to 51.89 emu/g, and Hc from 1939 Oe to 1312 Oe after that coercivity increases, which makes it a promising candidate for the magnetic applications.

Understanding the differences in CO2 adsorption in cementitious material is critical in mitigating the carbon footprint of the construction industry. This study chose the most common β-C2S phase in the industry as the cementitious material, selecting the β-C2S(111) and β-C2S(100) surfaces for CO2 adsorption. First-principles calculations were employed to systematically compare the CO₂ adsorption behaviors on both surfaces focusing on adsorption energy, adsorption configurations, and surface reconstruction. The comparison of CO₂ and H₂O adsorption behaviors on the β-C₂S(111) surface was also conducted to shed light on the influence of CO₂ on cement hydration. The adsorption energies of CO2 on these surfaces were determined as -0.647 and -0.423 eV, respectively, suggesting that CO2 adsorption is more energetically favorable on the β-C2S(111) surface than on the β-C2S(100) surface. The adsorption energy of H2O on the β-C2S(111) surface was 0.941 eV lower than that of CO2, implying that β-C2S tends to become hydrated before reacting with CO2. Bader charges, charge density differences, and the partial density of states were applied to characterize the electronic properties of CO2 and H2O molecules and those of the surface atoms. The initial Ca/O sites on the β-C2S(111) surface exhibited higher chemical reactivity due to the greater change in the average number of valence electrons in the CO2 adsorption. Specifically, after CO₂ adsorption, the average number of valence electrons for both the Ca and O atoms increased by 0.002 on the β-C2S(111) surface, while both decreased by 0.001 on the β-C2S(100) surface. In addition, due to the lower valence electron number of O atoms, the chemical reactivity of O atoms on the β-C2S(111) surface after H2O adsorption was higher than the case of CO2 adsorption, which favors the occurrence of further reactions. Overall, this work assessed the adsorption capacity of the β-C2S surface for CO2 molecules, offering a strong theoretical foundation for the design of novel cementitious materials for CO2 capture and storage.

The FeCoCrMnNiNx high entropy nitride ceramics thin films were prepared using the magnetron sputtering method, and the effects of nitrogen on the thin film properties were later examined. The addition of N2 affected the microstructure and its mechanical and corrosion properties. The addition of 2 and 3 sccm N2 by as much as 4.16 and 5.45 at% compared to the FeCoCrMnNi and 1 sccm N2 thin films changed the solid solution's crystalline structure (BCC+FCC) into an amorphous structure. The addition of nitrogen caused drastic changes to the surface morphology, creating a smoother and more uniform surface without cauliflower units. The AFM image analysis indicated that adding nitrogen reduced the surface roughness from 5.807 to 2.448 nm. Adding N2 to the CoCrFeMnNi thin film helped increase mechanical properties such as hardness, elasticity modulus, and strength. The FeCoCrMnNi thin film with a hardness of 8.75±0.5 GPa and an elasticity modulus of 257.37±11.4 GPa reached 12.67±1.2 and 194.39±12.4 GPa at 1 sccm N2. The applying coating of the CoCrFeMnNi thin film on the 304SUS increased corrosion resistance, while the addition of nitrogen to the CoCrFeMnNi thin film also improved corrosion resistance compared to the CoCrFeMnNi thin film.  

The underhand cut-and-fill mining method is widely employed in underground mines, especially when the surrounding rock mass or orebody is of poor quality or subjected to high stresses. Such a method typically requires the construction of sill mats with cemented backfill to provide operators with safe artificial roofs. It is critical to correctly estimate the minimum required strength of sill mat to minimize binder consumption and ensure its stability upon base exposure. Over the years, only a few publications were devoted to determining the minimum required cohesion (cmin) of sill mat. None of them took into account rock wall closure associated with the creep of surrounding rock mass. The effect of rock wall closure associated with rock creep on the cmin of sill mat remains unknown. To fill this gap, a series of numerical simulations were performed. The influence of rock creep on the cmin of base-exposed sill mat is, for the first time, investigated. The numerical results indicate that Mitchell's models could be suitable for large spanned sill mats subjected to negligible wall closure. This is however seldom the case in practice, especially when mine depth is large. In general, the cmin of sill mat increases as mine depth increases. Neglecting rock creep would lead to a significant underestimation of the cmin of sill mat. When mine depth is large and rock mass exhibits severe creep, the cemented backfill having a ductile behavior (i.e., with low stiffness but high strength) should be considered to reduce binder consumption and avoid crushing failure. In all cases, promptly filling the mined-out stope below the sill mat can improve the stability and reduce the cmin of sill mat.

This study successfully developed a series of carbon-sol reinforced copper (Cu-CS) composite coatings using electrodeposition with superiorly dispersed carbon sol to avoid nanoparticle aggregation. The carbon sol, characterized using transmission electron microscopy (TEM) and Zeta potential analyzer, consisted of carbon particles with an approximate diameter of 300 nm, uniformly distributed in the electrolytes. Characteristics of the composite coating were examined under scanning electron microscopy (SEM) observing its microstructures and X-ray diffraction (XRD) detecting the phase constituents. The sample's durability including wear resistance and corrosion resistance were also tested. Results indicate a significant improvement in coating thickness, density, and uniformity achieved for the Cu-CS composite coating at a carbon sol addition of 20mL/L. Moreover, it boasts a low wear volume (1.15×10-3 mm3), a high hardness (137.1 HV0.5), and a small corrosion rate (1.91×10-1 mm/year). The significant contribution of carbon particles in two factors improves the coating performance: strengthening effects and lubricating effects resulting from the incorporated carbon particles. Nevertheless, overdosage of carbon sol can compromise Cu-CS coating's microstructure, creating defects and undermining its functionality.

Abstract Fe-Cr-Ni austenitic alloys are extensively utilized in the hot-end components of nuclear light water reactors, turbine disks, and gas compressors. However, their low strength at elevated temperatures constrains their engineering applications. In this study, we developed a novel precipitation-strengthened alloy system by incorporating Al and Si elements into a FeCrNi equiatomic alloy. The results indicate that the FeCrNiAlxSix (at%, x = 0.1, 0.2) alloys possesses heterogeneous precipitation structure characterized by a micron-scale σ phase at the grain boundaries and a nano-scale BCC (B2) phase within the grains. An exceptional strength-ductility synergy across a wide temperature range is achieved in FeCrNiAl0.1Si0.1 alloy, attributed to the grain refinement and precipitation strengthening. Notably, at 873 K, a yield strength of 694 MPa, an ultimate tensile strength of 818 MPa, and a uniform elongation of 18 % are attained. The dislocation shearing mechanism for B2 phases and the Orowan bypass mechanism for σ phase, coupled with a high density of nano-twins and stacking faults in the matrix, contribute to the excellent mechanical properties at cryogenic and ambient temperatures. Moreover, the emergence of serrated σ phase and micro-twins in the matrix plays a crucial role in the strengthening and toughening mechanisms at intermediate temperatures. This study offers a novel perspective and strategy for the development of precipitation-hardened Fe-Cr-Ni austenitic alloys with exceptional strength-ductility synergy over a broad temperature range.

Owing to the orbital hybridization between the transition metal and the B element and the electron-trapping effect of the B element, transition metal borides are considered very promising materials for energy catalysis. In this work, an amorphous scaly high-entropy boride with electron traps was designed and fabricated via a facile reduction method to improve the hydrogen storage properties of magnesium hydride (MgH2). For dehydrogenation, the onset temperature of MgH2 + 10wt% HEB was dropped to 187.4 C, besides, the composite exhibited superior isothermal kinetics and the activation energy of the composite was reduced from 212.78 ± 3.93 kJ/mol to 65.04 ± 2.81 kJ/mol. In addition, MgH2 + 10wt% HEB could absorb hydrogen at 21.5 ℃, and 5.02 wt% H2 was charged in 50 min at 75 ℃. For reversible hydrogen storage capacity tests, the composite maintained a retention rate of 97% with 6.47 wt% hydrogen capacity after 30 cycles. Combining microstructure evidence with hydrogen storage performance, the catalytic mechanism was proposed. During ball milling, scaly high-entropy borides riveted a large number of heterogeneous active sites on the surface of MgH2. Driven by the cocktail effect as well as the orbital hybridization of metal borides, numerous active sites steadily enhanced the hydrogen storage reactions in MgH2.

7039 aluminum alloy is widely used in the vehicle armor field due to its high specific strength and fracture toughness. However, laminar tearing in the thickness plane of the base metal (BM), i.e., the normal direction (ND) - rolling direction (RD) plane, was occasionally found after welding of thick plates, resulting in premature failure of the material. In order to find out the reason for this, a vertically metal-inert gas (MIG) welded laminar tearing part of a 30 mm thick plate was analyzed. The texture, residual stress, microhardness and tensile properties were investigated. The results indicated that the crack extended along the RD as transcrystalline fracture and terminated at the BM. The grains near the crack grew preferentially in the (001) crystal direction. Furthermore, the tensile strength (83 MPa) and elongation (6.8%) in the RD were relatively higher than the ND. In particular, stronger texture, higher dislocation density, more Al7Cu2Fe phases, lower proportion of small-angle grain boundaries and the difference of grain size in different regions leading to the fragile microstructure were the root causes of crack initiation. The higher residual stress of the BM would promote the formation and extension of cracks. The restraining force due to fixture fixation and welding shrinkage force turned the crack to laminar tearing. Preventive measures of laminar tearing were also proposed.

Microwave absorbers have great potential for military and civil applications. Herein, Co0.5Zn0.5Fe2O4/residual carbon (CZFO/RC) composites have been successfully prepared using a hydrothermal method. RC was derived from coal gasification fine slag (CGFS) via pickling, which removes inorganic compounds. Multiple test means have been used to study the chemical composition, crystal structure, and micromorphology of the CZFO/RC composites, as well as their electromagnetic parameters and microwave absorption (MA) properties. The CZFO/RC composites exhibit excellent MA performance owing to their dielectric and magnetic losses. When the thickness of CZFO/RC-2 (FeCl3∙6H2O = 0.007 mol, ZnCl2 = 0.00175 mol, and CoCl2∙6H2O = 0.00175 mol) is 1.2 mm, the minimum reflection loss (RLmin) is −56.24 dB, whereas that at a thickness of 3 mm and 6.34 GHz, RLmin is −45.96 dB and the maximum effective absorption bandwidth is 1.83 GHz (5.53−7.36 GHz). Dielectric losses include interface and dipole polarizations, while magnetic losses include current and remnant magnetic losses. CZFO/RC-2 exhibits high impedance matching, allowing microwave to enter the absorber. The CST simulation confirms that CZFO/RC-2 considerably decreases the radar cross-section. This study can be used to promote the use of CGFS as EMW-absorbing materials.

Electrocatalytic N₂ reduction reaction (NRR) has been considered as a promising and alternative strategy for the synthesis of NH₃, which will contribute to the goal of carbon neutrality and sustainability. However, this process often suffers from the barrier for N₂ activation and competitive reactions, resulting in poor NH₃ yield and low Faraday efficiency (FE). Here, we report a two-dimensional ultrathin FeS nanosheets with high conductivity through a facile and scalable method under mild condition. The synthesized FeS catalysts can be used as the work electrode in the electrochemical NRR cell with N₂-saturated Na₂SO₄ electrolyte. Such a catalyst shows a NH₃ yield rate of 9.0 μg h^-1 mg_cat.^-1 and a high FE of 12.4%, which significantly outperformed the other most NRR catalysts. The high catalytic performance of FeS can be attributed to the 2D Mackinawite structure, which provides a new insight to explore low-cost and high-performance Fe-based electrocatalysts, as well as accelerates the practical application of the NRR.

Traditional resistive semiconductor gas sensors suffer from high operating temperature and poor selectivity. Herein, a highly selective NO2 sensor based on PbS quantum dots-PbMoO4-MoS2 ternary nanocomposites operating at room temperature was fabricated to address the issue. The ternary nanocomposites were synthesized via an in-situ method, yielding PbS quantum dots (QDs) with an average size of ~10 nm and PbMoO₄ nanoparticles in the 10-20 nm range, uniformly distributed on ultrathin MoS₂ nanosheets with an average thickness of ~7 nm. The optimized sensor demonstrated a significant improvement in response to 1 ppm NO₂ at 25°C, achieving a response of 44.5%, which is approximately seven times higher than that of the pure MoS₂-based sensor (6.4%). The sensor also achieved relatively short response/recovery times and full recovery properties. Notably, the optimal sensor displayed extraordinary selectivity towards NO2, showing negligible responses to different interfering gases. Density functional theory calculations were conducted to elucidate the underlying sensing mechanism, which was attributed to the enhanced specific surface area, the receptor function of both PbS QDs and PbMoO4 nanoparticles, along with the transducer function of MoS2 nanosheets.

To address the limitations associated with the conventional Fenton process, which often exhibits a restricted pH range and presents challenges in terms of catalyst recovery and second pollutant, an improved magnetic heterogeneous catalyst of halloysite/MnFe2O4 (HNT/MnFe2O4) was optimally synthesized. It showed that HNT/MnFe2O4 catalysts could achieve 90% removal efficiency to 50 mg/L of methylene blue (MB) at pH 4–10 with high utilization of hydrogen peroxide (H2O2), and the used HNT/MnFe2O4 catalysts could be easily separated from solution via magnetic separation. The presence of anions (NO3-, Cl-, SO42-, CO32- and HCO3-) and HA scarcely affected the degradation of MB by HNT/MnFe2O4 catalysts and the removal efficiency of MB only decreased by less than 10% in the 5th cycle compared to the fresh catalyst. Furthermore, HNT/MnFe2O4 catalysts demonstrated their capability to effectively degrade various organic pollutants such as benzohydroxamic acid, xanthate, and eosin Y. The excellent catalytic performance of HNT/MnFe2O4 catalysts was attributed to the synergistic effects between HNT and MnFe2O4. The EPR spectra and quenching experiments indicated that the main reactive oxygen species (ROS) that participated in the degradation process were ·OH and ·O2-. ·OH directly attacks MB molecular and ·O2- accelerates the reduction of metal ions. Therefore, HNT/MnFe2O4 catalysts demonstrated a good potential for organic pollutant degradation. This study provides valuable insights into the synthesis of novel catalysts and their practical applications in organic wastewater purification.

Non-stoichiometric carbides have been proven to be effective electromagnetic wave (EMW) absorbing materials. In this study, phase and morphology of MZnC(M=Co/Fe/Cu) loaded on a 3D network structure melamine sponge (MS) carbon composites were investigated through vacuum filtration followed by calcination. The FeZnC/CoZnC/CuZnC with carbon nanotubes (CNTs) were uniformly dispersed on the surface of melamine sponge carbon skeleton and Co-containing sample exhibits the highest CNTs concentration. The minimum reflection loss (RLmin) of the CoZnC/MS composite (with a paraffin filling ratio of 1:1) reached -33.6 dB, and the effective absorption bandwidth (EAB) reached 9.6 GHz. The outstanding electromagnetic wave absorption (EMWA) properties of the CoZnC/MS composite can be attributed to its unique hollow structure, which leads to multiple reflections and scattering. The formed conductive network improves dielectric and conductive loss. The incorporation of Co enhances the magnetic loss capability and optimizes interfacial polarization and dipole polarization. By simultaneously improving dielectric and magnetic losses, excellent impedance matching performance is achieved. The clarification of element replacement in MZnC/MS composites provides an efficient design perspective for high-performance non-stoichiometric carbide EMW absorbers.

The development of high-performance functional composite materials has become a research hotspot in response to the hazards of overheating and electromagnetic radiation on modern electronic devices. Herein, we grew magnetic Fe3O4 particles in situ on the MXene layer to obtain the MXene@Fe3O4 composites with rich heterogeneous interfaces. Owing to the unique heterostructure and synergistic effects of the multiple electromagnetic wave absorption mechanisms, the composite achieved a minimum reflection loss of -27.14 dB and an effective absorption bandwidth of 2.05 GHz at an absorber thickness of 2.98 mm. Moreover, the MXene@Fe3O4 composites could be encapsulated in thermoplastic polyurethane (TPU) by a thermal curing method. The obtained composite elastomer exhibited a stronger tensile strength, and its thermal diffusivity was 113% higher than that of pure TPU. Such additional mechanical properties and thermal conduction feature make this composite elastomer possible as an advanced electromagnetic absorber to adapt to the ever-changing environment for expanding more practical applications.

Interstitial oxygen (O) contamination is still a huge obstacle for metal injection molding (MIM) titanium alloys. Herein, we successfully solve this critical problem by regulating the thermal debinding temperature and adding the oxygen scavenger LaB6. The result shows that the surface oxide layer (with the thickness of 13.4±0.5 nm) of Ti6Al4V powder begins to dissolve into Ti matrix within the temperature range of 663-775°C. Reducing the thermal debinding temperature and adding LaB6 powder can collectively prevent O contamination for MIM Ti alloys. Benefit from the decrease of dissolved O content, the slips of mixed anddislocations are effectively accelerated, thus achieving an increase in ductility. Moreover, the grain refinement and in situ formed TiB whiskers and second-phase La2O3 particles contribute to the improvement in strength. The fabricated MIM Ti6Al4V sample exhibits the excellent mechanical properties, with the ultimate tensile strength of 967±5 MPa, yield strength of 866±8 MPa and elongation of 21.4±0.7%. The tensile properties are an outstanding practice in the reported literatures for MIM Ti6Al4V alloys. This study provides an effective guidance for the development of high-performance MIM Ti alloys and other metal materials.

As a novel 2D material, Ti3C2Tx-MXene has attracted many researchers’ attention in the field of microwave absorption (MA). However, the MA effect of common Ti3C2Tx-MXene is not prominent and often requires complex processes or combinations of other materials to achieve better performance. In this context, a kind of gradient woodpile structures using common Ti3C2Tx-MXene as MA material were designed and manufactured through direct ink writing (DIW) 3D printing. The minimum reflection loss (RLmin) of the Ti3C2Tx-MXene based gradient woodpile structures with a thickness less than 3mm can reach -70dB, which is significantly improved compared with the full-filled structure. In addition, the effective absorption bandwidth (EAB) achieves 7.73 GHz. This work demonstrates that the common Ti3C2Tx-MXene Material can successfully achieve excellent MA performance and tunable frequency band through macroscopic structural design and DIW 3D printing, without the need for complex material hybridization and modification. It has broad application prospects in reducing electromagnetic wave radiation and interference.

In this work, a series of high-entropy ceramics which nominal composition (Mg1/2Zn1/2)0.4+xLi0.4(Ca1/2Sr1/2)0.4-xTiO3 (0 ≤ x ≤ 0.4) have been successfully synthesized using the conventional solid-phase method. The (Mg1/2Zn1/2)0.4+xLi0.4(Ca1/2Sr1/2)0.4-xTiO3 ceramics were confirmed to be composed of the main phase (Zn, Mg, Li)TiO3 and the secondary phase Ca0.5Sr0.5TiO3 by XRD, Rietveld refinement and EDS analysis. The quality factor (Qf) of the samples is inversely proportional to the content of the Ca0.5Sr0.5TiO3 phase, and it is influenced by the density. The secondary phase and molecular polarizability (αT) have a significant impact on the dielectric constant (εr) of the samples. Moreover, the temperature coefficient of resonant frequency (τf) of the samples is determined by the distortion of [TiO6] octahedra and the secondary phase with a positive τf value. (Mg1/2Zn1/2)0.4+xLi0.4(Ca1/2Sr1/2)0.4-xTiO3 ceramics achieved ideal microwave dielectric properties (εr = 17.6, Qf = 40,900 GHz, τf = -8.6 ppm/°C) when x = 0.35. Therefore, (Mg1/2Zn1/2)0.4+xLi0.4(Ca1/2Sr1/2)0.4-xTiO3 ceramics possess the potential for application in wireless communication, and a new approach has been provided to enhance the performance of microwave dielectric ceramics.

Aqueous zinc-ion batteries (AZIBs) are regarded as promising electrochemical energy storage systems for various applications because of their high safety, low cost, and high capacity. However, dendrite formation and side reactions occurring during zinc plating/stripping, greatly reduce the capacity and cycle life of the battery and subsequently limit its practical application. To address these issues, the surface of the zinc anode was modified by functional double layers, which consist of a zincophilic Cu layer and a flexible polymer layer. The zincophilic Cu interfacial layer was prepared by CuSO4 solution pretreatment, which works as a nucleation site to guide uniform Zn deposition, while the polymer layer acting as a protective layer was coated onto the Cu interface layer to prevent side reactions between zinc and electrolytes. Benefiting from the synergistic effect of a zincophilic Cu layer and a polymer protective layer, the symmetric battery exhibits an impressive cycle life of over 2900 hours at the current density of 1 mA·cm-2 with the capacity of 1 mAh·cm-2. Moreover, the full battery paired with vanadium oxide cathode achieves a remarkable capacity retention of 72% even after 500 cycles.

The Fe1-xNixVO4 (where x = 0, 0.05, 0.1, and 0.2) nanoparticles in this work were successfully synthesized via a co-precipitation method. The structural, magnetic and electrochemical properties of the prepared Fe1-xNixVO4 nanoparticles were studied as a function of Ni content. The experimental results show that the prepared Ni-doped FeVO4 samples have a triclinic structure. Scanning electron microscopy (SEM) images reveal a decrease in average nanoparticle size with increasing Ni content, leading to an enhancement in both specific surface area and magnetization values. X-ray absorption near edge structure (XANES) analysis confirms the substitution of Ni²⁺ ions into Fe³⁺ sites. The magnetic investigation reveals that Ni-doped FeVO4 exhibits weak ferromagnetic behavior at room temperature, in contrast to the antiferromagnetic behavior observed in the undoped FeVO4. Electrochemical studies demonstrate that the Fe0.95Ni0.05VO4 electrode achieves the highest specific capacitance of 334.05 F/g at a current density of 1 A/g, which is attributed to its smallest average pore diameter. On the other hand, the enhanced specific surface of the Fe0.8Ni0.2VO4 electrode is responsible for its outstanding cyclic stability. Overall, our results suggest that the magnetic and electrochemical properties of FeVO4 nanoparticles could be effectively tuned by varying Ni doping contents.

As a refractory iron ore, achieving clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal. In this study, the microwave fluidization magnetization roasting of limonite was explored. The micro-morphology, microstructure, and mineral phase transformation of the roasted products were meticulously analyzed using scanning electron microscope (SEM), automatic surface area and porosity analyzer, X-ray diffractometer (XRD), and vibrating sample magnetometer (VSM). Additionally, kinetic analysis was conducted to identify the factors limiting the roasting reaction rate. Microwave fluidization roasting has significantly increased the specific surface area of limonite, increased the opportunity of CO and limonite, and accelerated the transformation from FeO(OH) and then to α-Fe2O3 and subsequently to Fe3O4. In addition, the water in the limonite ore and the newly formed magnetite have a strong microwave absorption capacity, which has a certain activation effect on the reduction roasting of limonite. At a temperature of 773 K, the saturation specific magnetization intensity and maximum specific magnetization coefficient increased to 23.08 A·m2·kg−1 and 2.50 × 10−4 m3·kg−1, respectively. The subsequent magnetic separation of the reconstructed limonite yielded an iron concentrate with a Fe grade of 59.26 wt% and a recovery of 90.07 wt%. Kinetic analysis revealed that the reaction mechanism function model was consistent with the diffusion model D1, with the mechanism function described as k=0.08208exp(−20.3441/RgT). Microwave fluidization roasting demonstrates significant potential in the beneficiation of limonite, offering a promising approach for the exploitation of refractory iron ores.

Calcium-magnesium-alumina-silicate (CMAS) and/or molten salt corrosion has attracted increased attentions, which is an important cause of thermal barrier coatings (TBCs) failure. In this study, the effect of CMAS and NaCl melting sequence on the corrosion mechanisms of the Yttria-stabilised zirconia (YSZ) TBCs was revealed through experiments and finite element simulations. The YSZ TBCs were prepared via an atmospheric plasma spraying. Subsequently, the CMAS and NaCl corrosion experiments of the TBCs were conducted at 1250℃. The results indicated that the melting sequence of CMAS and NaCl could affect the TBCs failure mode. The coating failure modes of after CMAS+NaCl mixed corrosion and firstly melting NaCl, with secondly melting CMAS corrosion were the buckling failure, and conversely the coating failure mode was the spalling failure. This study provides data support for the optimization of TBC system in complex corrosive environments.

Hemimorphite exhibits poor floatability during the sulfidization flotation process. The addition of Cu2+ and Pb2+ enhances the reaction activity of the hemimorphite surface and subsequently improves its flotation behavior. In this study, the adsorption mechanisms of Cu2+ and Pb2+ onto a hemimorphite surface were investigated. We examined the interaction mechanism of xanthate with the hemimorphite surface and observed changes in the mineral surface hydrophobicity after synergistic activation by with Cu2+ and Pb2+. Microflotation tests indicated that the individual activation of Cu2+ or Pb2+ on the hemimorphite surfaces increased the flotation recovery, with Pb2+ showing greater effectiveness than Cu2+. The synergistic activation with Cu2+ and Pb2+ significantly boosted the flotation recovery of hemimorphite. Both Cu2+ and Pb2+ can be adsorbed onto hemimorphite surfaces, forming an adsorption layer containing Cu or Pb components. Following synergistic activation with Cu2+ and Pb2+, the activated layer on the hemimorphite surfaces consisted of both Cu and Pb components, which contained a higher content of the active product than when activated by Cu2+ or Pb2+. Additionally, the adsorption of xanthate on the hemimorphite surfaces increased noticeably after synergistic activation with Cu2+ and Pb2+, suggesting a more vigorous reaction between xanthate and the activated minerals. Therefore, synergistic activation with Cu2+ and Pb2+ effectively increased the content of active products on the hemimorphite surfaces, enhanced mineral surface reactivity, facilitated collector adsorption, and improved mineral surface hydrophobicity.

This study aims to investigate the mechanical properties and damage characteristics of gangue cemented filling materials (CGBM) under true triaxial compression. The true triaxial compression tests, CT scanning, SEM, and EDS tests were conducted on cemented gangue backfill samples (CGBS) with various carbon nanotube concentrations (PCNT) that satisfied fractal theory for particle size distribution (PSD) of aggregates. The mechanical properties, energy dissipations, and failure mechanisms of the CGBS under true triaxial compression were systematically analyzed. The results indicate that appropriate carbon nanotubes (CNTs) effectively enhance the mechanical properties and energy dissipations of CGBS through micropore filling and microcrack bridging, and the optimal effect appears at PCNT = 0.08%. Taking PSD fractal dimension (D) of 2.5 as an example, compared to CGBS without CNT, the peak strength (σp), axial peak strain (ɛ1p), elastic strain energy (Ue), and dissipated energy (Ud) increased by 12.76%, 29.60%, 19.05%, 90.39%, respectively. However, excessive CNTs worse the mechanical properties of CGBS due to CNT agglomeration, manifesting a decrease in σp, ɛ1p, and Δɛv when PCNT increases from 0.08% to 0.12%. Moreover, the addition of CNTs improved the integrity of CGBS after macroscopic failure, and crack extension in CGBS appeared in two modes: detour and pass through the aggregates. The σp and Ud firstly increase and then decrease with increasing D, and porosity shows the opposite trend. The ɛ1p and Δɛv are negatively correlated with D, and CGBS with D = 2.15 has the maximum deformation parameters (ɛ1p = 0.05079, Δɛv = 0.01990) due to the frictional slip effect caused by coarse aggregates. With increasing D, the failure modes of CGBS transition from oblique shear failure to “Y-shaped” shear failure, and then further transform into conjugate shear failure. The study will contribute to a better understanding of the mechanical properties and failure characteristics of CGBS under true triaxial compression.

W-type barium nickel ferrite (BaNi2Fe16O27) is highly promising for electromagnetic wave (EMW) absorption due to the magnetic loss capability to EMWs, low cost, large-scale production capabilities, high temperature resistance, and excellent chemical stability. However, the poor dielectric loss hampers the utilization of magnetic ferrites, resulting in the difficulty in improving the EMW absorption performance. Developing more efficient strategies to improve the EMW absorption of ferrite is highly desired yet remains challenging. Here, an efficient substitution strategy of using rare earth La3+ to substitute Ba2+ in W-type ferrite was achieved, leading to the preparation of novel La-substituted ferrites (Ba1-xLaxNi2Fe15.4O27). The influences of La3+ substitution on ferrites' EMW absorption and the dissipative mechanism toward EMWs were systematically explored and discussed. Particularly, the introduction of La3+ efficiently induced lattice defects, enhanced defect-induced polarization ability, and reduced the material's bandgap, thereby leading to the enhanced dielectric properties of ferrites. The presence of La3+ also enhanced the ferromagnetic resonance loss to strengthen the magnetic properties. This contributed to the significantly improved EMW absorption of Ba1-xLaxNi2Fe15.4O27 in comparison to the pure W-type ferrites, e.g., when x = 0.2, the best EMW absorption performance was obtained with a minimum reflection loss of −55.6 dB and an effective absorption bandwidth of 3.44 GHz.

With the wide application of electromagnetic wave, a high performance electromagnetic shielding material is urgently needed to solve the harm caused by electromagnetic wave. Complete cross-linking strategy is adopted in this paper. Polyacrylamide (PAM) was synthesized by in-situ polymerization of AM (acrylamide) monomer. The obtained PAM was blended with polyethylene glycol (PEG) to prepare PAM/PEG hydrogels and form rigid support structures. Subsequently, the modified carbon nanotubes (S-CNTs) were incorporated into sodium alginate (SA) and PAM/PEG. Finally, Na+ was used to trigger SA self-assembly, which significantly improved the mechanical properties and electrical conductivity of the hydrogels, and prepared PAM/PEG/SA/S-CNTs-Na hydrogels with high toughness and strong electromagnetic shielding (EMI). The results showed that the compressive strength of PAM/PEG/SA/S-CNTs-Na hydrogel was 19.05 MPa, while that of PAM/PEG hydrogel was 17.69 MPa, which was 107.69% higher than that of PAM/PEG hydrogel. More encouraging, the total electromagnetic shielding efficiency (SET) of PAM/PEG/SA/S-CNTs-Na hydrogels at a thickness of only 3 mm and a CNTs content of 20 wt% was 32.92 dB, 213.17% higher than that of PAM/PEG hydrogels (15.44 dB).

Amino acids have emerged as promising green alternatives to replace toxic inhibitors in corrosion protection applications. In this study, we present a one-step synthetic approach for the functionalization of methionine and cysteine using p-tert-butylbenzoic acid (P-Meth and P-Cys), which have super protective performance to metals against corrosions. The corrosion rates of Q235 steel in 1 M HCl were reduced from 4.542 to 0.202 and 0.312 mg·h-1cm-2 in the presence of 100 mg·h-1 P-Meth and P-Cys, respectively. The surface structures of Q235 steel were not broken after 12 h in 1 M HCl mediums. The charge transfer resistances of corrosion reactions were enhanced by 12 and 9 times in the presence of P-Meth and P-Cys, respectively. Both of P-Meth and P-Cys were adsorbed onto Q235 steel by chemical actions generally, accompanying with a little physical action. Molecular dynamic simulations demonstrate that P-Meth has higher binding energies onto Q235 steel than P-Cys. The study is significant for the corrosion protections of metals with green and environmental-friend methods.

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.

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 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

 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.

Electrochemical metallurgy at low temperatures (temperature <473 K) is promising for the extracting/refining metals and alloys in a green and sustainable way. However, the kinetics of electrodeposition process is generally slow at the low-temperature, which causes unexpected large overpotential and low efficiency. Thus, external physical fields are effective strategies for improving the mass transfer process and charge transfer process of electrochemical reaction. The rates of mass transfer and charge transfer determine the magnitude of overpotential and higher overpotential leads to lower energy efficiency, which in turn reduces the efficiency of the electrochemical process. In this review, we introduced the challenge in low-temperature electrochemical process. The recent achievements in the optimization of electrodeposition processes by applying an external physical field are briefly discussed. From the aspects of equipment and mechanism, summarized the regulating effects on optimization of electrodeposition process and selection strategies of diverse external physical fields, consisting of magnetic, ultrasonic and supergravity fields. Finally, advanced methods for in-situ characterization of external physical field-assisted electrodeposition processes are summarized to deeply understand of the metallic electrodeposition. In-depth mechanism of the external physical field on the electrode process is helpful for promoting the efficient of extracting metals at low temperatures.

Recent advancements in electrocatalysis have highlighted the exceptional application value of amorphous electrocatalysts, which with unique atomic configurations, exhibited superior catalytic performance compared to those of their crystalline counterparts. Transition metal (TM) amorphous ribbon-shaped electrocatalysts have recently emerged as a new frontier in the catalysis field. Dealloying is widely considered a fascinating method for promoting the performance of electrocatalysts. In this review, we comprehensively examine the principles of water electrolysis, discuss the prevalent methods for fabricating ribbon-configured electrocatalysts, and provide an overview of amorphous alloys. Further, we discuss binary, ternary, and high-entropy amorphous TM-based electrocatalysts, which satisfy the requirements for performing water electrolysis. We also propose strategies to enhance the activity of amorphous TM-based ribbons, including morphology control, defect engineering, composition optimization, and heterostructure creation in different electrolytes. We focus on the latest developments in the design of heterogeneous micro/nanostructures, control over preparation techniques, and synthesis of different compositions. Finally, we discuss the ongoing challenges and provide a perspective on the future development of broadly applicable, self-supporting TM ribbon-shaped electrocatalysts.

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.

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.

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.