Search2023 Vol. 30, No. 1
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2023, vol. 30, no. 1, pp.
1-13.
https://doi.org/10.1007/s12613-022-2541-1
Abstract:
The olivine-type lithium iron phosphate (LiFePO4) cathode material is promising and widely used as a high-performance lithium-ion battery cathode material in commercial batteries due to its low cost, environmental friendliness, and high safety. At present, LiFePO4/C secondary batteries are widely used for electronic products, automotive power batteries, and other occasion-related applications with good thermal stability, stable cycle performance, and low room-temperature self-discharge rate. However, LiFePO4-based battery applications are seriously limited when they are operated in a cold climate. This outcome is due to a considerable decrease in Li+ transport capabilities within the electrode, particularly leading to a dramatic decrease in the electrochemical capacity and power performance of the electrolyte. Therefore, the design of low-temperature electrolytes is important for the further commercial application of LiFePO4 batteries. This paper reviews the key factors for the poor low-temperature performance of LiFePO4-based batteries and the research progress of low-temperature electrolytes. Special attention is paid to electrolyte components, including lithium salts, cosolvents, additives, and the development of new electrolytes. The factors affecting the anode are also analyzed. Finally, according to the current research progress, some viewpoints are summarized to provide suitable modification methods and research suggestions for improving the practicability of LiFePO4/C commercial batteries at low temperatures in the future.
The olivine-type lithium iron phosphate (LiFePO4) cathode material is promising and widely used as a high-performance lithium-ion battery cathode material in commercial batteries due to its low cost, environmental friendliness, and high safety. At present, LiFePO4/C secondary batteries are widely used for electronic products, automotive power batteries, and other occasion-related applications with good thermal stability, stable cycle performance, and low room-temperature self-discharge rate. However, LiFePO4-based battery applications are seriously limited when they are operated in a cold climate. This outcome is due to a considerable decrease in Li+ transport capabilities within the electrode, particularly leading to a dramatic decrease in the electrochemical capacity and power performance of the electrolyte. Therefore, the design of low-temperature electrolytes is important for the further commercial application of LiFePO4 batteries. This paper reviews the key factors for the poor low-temperature performance of LiFePO4-based batteries and the research progress of low-temperature electrolytes. Special attention is paid to electrolyte components, including lithium salts, cosolvents, additives, and the development of new electrolytes. The factors affecting the anode are also analyzed. Finally, according to the current research progress, some viewpoints are summarized to provide suitable modification methods and research suggestions for improving the practicability of LiFePO4/C commercial batteries at low temperatures in the future.
2023, vol. 30, no. 1, pp.
14-24.
https://doi.org/10.1007/s12613-022-2519-z
Abstract:
Hydrogen is an ideal clean energy because of its high calorific value and abundance of sources. However, storing hydrogen in a compact, inexpensive, and safe manner is the main restriction on the extensive utilization of hydrogen energy. Magnesium (Mg)-based hydrogen storage material is considered a reliable solid hydrogen storage material with the advantages of high hydrogen storage capacity (7.6wt%), good performance, and low cost. However, the high thermodynamic stability and slow kinetics of Mg-based hydrogen storage materials have to be overcome. In this paper, we will review the recent advances in the nanoconfinement of Mg-related hydrogen storage materials by loading Mg particles on different supporting materials, including carbons, metal–organic frameworks, and other materials. Perspectives are also provided for designing high-performance Mg-based materials using nanoconfinement.
Hydrogen is an ideal clean energy because of its high calorific value and abundance of sources. However, storing hydrogen in a compact, inexpensive, and safe manner is the main restriction on the extensive utilization of hydrogen energy. Magnesium (Mg)-based hydrogen storage material is considered a reliable solid hydrogen storage material with the advantages of high hydrogen storage capacity (7.6wt%), good performance, and low cost. However, the high thermodynamic stability and slow kinetics of Mg-based hydrogen storage materials have to be overcome. In this paper, we will review the recent advances in the nanoconfinement of Mg-related hydrogen storage materials by loading Mg particles on different supporting materials, including carbons, metal–organic frameworks, and other materials. Perspectives are also provided for designing high-performance Mg-based materials using nanoconfinement.
2023, vol. 30, no. 1, pp.
25-32.
https://doi.org/10.1007/s12613-022-2441-4
Abstract:
Cost-effective, safe, and highly performing energy storage devices require rechargeable batteries, and among various options, aqueous zinc-ion batteries (ZIBs) have shown high promise in this regard. As a cathode material for the aqueous ZIBs, manganese dioxide (MnO2) has been found to be promising, but certain drawbacks of this cathode material are slow charge-transfer capability and poor cycling performance. Herein, a novel design of graphene quantum dots (GQDs) integrated with Zn-intercalated MnO2 nanosheets is put forward to construct a 3D nanoflower-like GQDs@ZnxMnO2 composite cathode for aqueous ZIBs. The synergistic coupling of GQDs modification with Zn intercalation provides abundant active sites and conductive medium to facilitate the ion/electron transmission, as well as ensure the GQDs@ZnxMnO2 composite cathode with enhanced charge-transfer capability and high electrochemical reversibility, which are elucidated by experiment results and in-situ Raman investigation. These impressive properties endow the GQDs@ZnxMnO2 composite cathode with superior aqueous Zn2+ storage capacity (~403.6 mAh·g−1), excellent electrochemical kinetics, and good structural stability. For actual applications, the fabricated aqueous ZIBs can deliver a substantial energy density (226.8 W·h·kg−1), a remarkable power density (650 W·kg−1), and long-term cycle performance, further stimulating their potential application as efficient electrochemical storage devices for various energy-related fields.
Cost-effective, safe, and highly performing energy storage devices require rechargeable batteries, and among various options, aqueous zinc-ion batteries (ZIBs) have shown high promise in this regard. As a cathode material for the aqueous ZIBs, manganese dioxide (MnO2) has been found to be promising, but certain drawbacks of this cathode material are slow charge-transfer capability and poor cycling performance. Herein, a novel design of graphene quantum dots (GQDs) integrated with Zn-intercalated MnO2 nanosheets is put forward to construct a 3D nanoflower-like GQDs@ZnxMnO2 composite cathode for aqueous ZIBs. The synergistic coupling of GQDs modification with Zn intercalation provides abundant active sites and conductive medium to facilitate the ion/electron transmission, as well as ensure the GQDs@ZnxMnO2 composite cathode with enhanced charge-transfer capability and high electrochemical reversibility, which are elucidated by experiment results and in-situ Raman investigation. These impressive properties endow the GQDs@ZnxMnO2 composite cathode with superior aqueous Zn2+ storage capacity (~403.6 mAh·g−1), excellent electrochemical kinetics, and good structural stability. For actual applications, the fabricated aqueous ZIBs can deliver a substantial energy density (226.8 W·h·kg−1), a remarkable power density (650 W·kg−1), and long-term cycle performance, further stimulating their potential application as efficient electrochemical storage devices for various energy-related fields.
2023, vol. 30, no. 1, pp.
33-43.
https://doi.org/10.1007/s12613-022-2416-5
Abstract:
Pyrolytic graphite (PG) with highly aligned graphene layers, present anisotropic electrical and thermal transport behavior, which is attractive in electronic, electrocatalyst and energy storage. Such pristine PG could meeting the limit of electrical conductivity (~2.5 × 104 S·cm−1), although efforts have been made for achieving high-purity sp2 hybridized carbon. For manipulating the electrical conductivity of PG, a facile and efficient electrochemical strategy is demonstrated to enhance electrical transport ability via reversible intercalation/de-intercalation of\begin{document}${\rm{ AlCl}}^{-}_4 $\end{document} ![]()
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Pyrolytic graphite (PG) with highly aligned graphene layers, present anisotropic electrical and thermal transport behavior, which is attractive in electronic, electrocatalyst and energy storage. Such pristine PG could meeting the limit of electrical conductivity (~2.5 × 104 S·cm−1), although efforts have been made for achieving high-purity sp2 hybridized carbon. For manipulating the electrical conductivity of PG, a facile and efficient electrochemical strategy is demonstrated to enhance electrical transport ability via reversible intercalation/de-intercalation of
2023, vol. 30, no. 1, pp.
44-53.
https://doi.org/10.1007/s12613-021-2372-5
Abstract:
The practical application of magnesium hydride (MgH2) was seriously limited by its high desorption temperature and slow desorption kinetics. In this study, a bullet-like catalyst based on vanadium related MOFs (MOFs-V) was successfully synthesized and doped with MgH2 by ball milling to improve its hydrogen storage performance. Microstructure analysis demonstrated that the as-synthesized MOFs was consisted of V2O3 with a bullet-like structure. After adding 7wt% MOFs-V, the initial desorption temperature of MgH2 was reduced from 340.0 to 190.6°C. Besides, the MgH2+7wt%MOFs-V composite released 6.4wt% H2 within 5 min at 300°C. Hydrogen uptake was started at 60°C under 3200 kPa hydrogen pressure for the 7wt% MOFs-V containing sample. The desorption and absorption apparent activity energies of the MgH2+7wt%MOFs-V composite were calculated to be (98.4 ± 2.9) and (30.3 ± 2.1) kJ·mol−1, much lower than (157.5 ± 3.3) and (78.2 ± 3.4) kJ·mol−1 for the as-prepared MgH2. The MgH2+7wt%MOFs-V composite exhibited superior cyclic property. During the 20 cycles isothermal dehydrogenation and hydrogenation experiments, the hydrogen storage capacity stayed almost unchanged. X-ray diffraction (XRD) and X-ray photoelectron spectrometer (XPS) measurements confirmed the presence of metallic vanadium in the MgH2+7wt%MOFs-V composite, which served as catalytic unit to markedly improve the hydrogen storage properties of Mg/MgH2 system.
The practical application of magnesium hydride (MgH2) was seriously limited by its high desorption temperature and slow desorption kinetics. In this study, a bullet-like catalyst based on vanadium related MOFs (MOFs-V) was successfully synthesized and doped with MgH2 by ball milling to improve its hydrogen storage performance. Microstructure analysis demonstrated that the as-synthesized MOFs was consisted of V2O3 with a bullet-like structure. After adding 7wt% MOFs-V, the initial desorption temperature of MgH2 was reduced from 340.0 to 190.6°C. Besides, the MgH2+7wt%MOFs-V composite released 6.4wt% H2 within 5 min at 300°C. Hydrogen uptake was started at 60°C under 3200 kPa hydrogen pressure for the 7wt% MOFs-V containing sample. The desorption and absorption apparent activity energies of the MgH2+7wt%MOFs-V composite were calculated to be (98.4 ± 2.9) and (30.3 ± 2.1) kJ·mol−1, much lower than (157.5 ± 3.3) and (78.2 ± 3.4) kJ·mol−1 for the as-prepared MgH2. The MgH2+7wt%MOFs-V composite exhibited superior cyclic property. During the 20 cycles isothermal dehydrogenation and hydrogenation experiments, the hydrogen storage capacity stayed almost unchanged. X-ray diffraction (XRD) and X-ray photoelectron spectrometer (XPS) measurements confirmed the presence of metallic vanadium in the MgH2+7wt%MOFs-V composite, which served as catalytic unit to markedly improve the hydrogen storage properties of Mg/MgH2 system.
2023, vol. 30, no. 1, pp.
54-62.
https://doi.org/10.1007/s12613-022-2510-8
Abstract:
MgH2 with a large hydrogen capacity is regarded as a promising hydrogen storage material. However, it still suffers from high thermal stability and sluggish kinetics. In this paper, highly dispersed nano-Ni has been successfully prepared by using the polyol reduction method with an average size of 2.14 nm, which significantly improves the de/rehydrogenation properties of MgH2. The MgH2–10wt% nano-Ni sample starts releasing H2 at 497 K, and roughly 6.2wt% H2 has been liberated at 583 K. The rehydrogenation kinetics of the sample are also greatly improved, and the adsorption capacity reaches 5.3wt% H2 in 1000 s at 482 K and under 3 MPa hydrogen pressure. Moreover, the activation energies of de/rehydrogenation of the MgH2–10wt% nano-Ni sample are reduced to (88 ± 2) and (87 ± 1) kJ·mol−1, respectively. In addition, the thermal stability of the MgH2–10wt% nano-Ni system is reduced by 5.5 kJ per mol H2 from that of pristine MgH2. This finding indicates that nano-Ni significantly improves both the thermodynamic and kinetic performances of the de/rehydrogenation of MgH2, serving as a bi-functional additive of both reagent and catalyst.
MgH2 with a large hydrogen capacity is regarded as a promising hydrogen storage material. However, it still suffers from high thermal stability and sluggish kinetics. In this paper, highly dispersed nano-Ni has been successfully prepared by using the polyol reduction method with an average size of 2.14 nm, which significantly improves the de/rehydrogenation properties of MgH2. The MgH2–10wt% nano-Ni sample starts releasing H2 at 497 K, and roughly 6.2wt% H2 has been liberated at 583 K. The rehydrogenation kinetics of the sample are also greatly improved, and the adsorption capacity reaches 5.3wt% H2 in 1000 s at 482 K and under 3 MPa hydrogen pressure. Moreover, the activation energies of de/rehydrogenation of the MgH2–10wt% nano-Ni sample are reduced to (88 ± 2) and (87 ± 1) kJ·mol−1, respectively. In addition, the thermal stability of the MgH2–10wt% nano-Ni system is reduced by 5.5 kJ per mol H2 from that of pristine MgH2. This finding indicates that nano-Ni significantly improves both the thermodynamic and kinetic performances of the de/rehydrogenation of MgH2, serving as a bi-functional additive of both reagent and catalyst.
2023, vol. 30, no. 1, pp.
63-71.
https://doi.org/10.1007/s12613-021-2368-1
Abstract:
The effect of Mg replacement with Al on the discharge capacity of Mg2Cu powder mixture was investigated. The mixture of nanocrystalline powder was prepared via mechanical alloying (MA) technique with a high energy planetary ball mill. In addition, different moles of Al (0.05, 0.1, 0.15, 0.2, and 0.3 M) were substituted to Mg2Cu powder. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze changes in structure, morphology, and grain size. The obtained powder was utilized as an anode in a nickel–metal hydride battery (Ni–MH). In the specimens with 0.05 M Al content, the orthorhombic structure of Mg2Cu is emerged after 5 h milling. The results reveal that more than 0.1 M Al substitution leads to an appearance of MgCu2 peaks. Al substitution does not affect microstructure uniformity; however, it causes a decrease in crystalline size and lattice parameters. The selected area diffraction (SAD) pattern elucidates that the electrode with the Mg1.9Al0.1Cu chemical composition and 20 h milling has the maximum discharge capacity.
The effect of Mg replacement with Al on the discharge capacity of Mg2Cu powder mixture was investigated. The mixture of nanocrystalline powder was prepared via mechanical alloying (MA) technique with a high energy planetary ball mill. In addition, different moles of Al (0.05, 0.1, 0.15, 0.2, and 0.3 M) were substituted to Mg2Cu powder. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze changes in structure, morphology, and grain size. The obtained powder was utilized as an anode in a nickel–metal hydride battery (Ni–MH). In the specimens with 0.05 M Al content, the orthorhombic structure of Mg2Cu is emerged after 5 h milling. The results reveal that more than 0.1 M Al substitution leads to an appearance of MgCu2 peaks. Al substitution does not affect microstructure uniformity; however, it causes a decrease in crystalline size and lattice parameters. The selected area diffraction (SAD) pattern elucidates that the electrode with the Mg1.9Al0.1Cu chemical composition and 20 h milling has the maximum discharge capacity.
2023, vol. 30, no. 1, pp.
72-81.
https://doi.org/10.1007/s12613-022-2466-8
Abstract:
The effect of rolling and forging on the microstructure and corrosion behavior of LZ91 alloy was investigated using an electron probe micro-analyzer, immersion and electrochemical tests. Results showed that the area fraction of the β-Li phase remained unchanged, and the grain size of the β-Li phase decreased after forging. The as-rolled forged alloy (FR-LZ91) exhibited the highest area fraction of the β-Li phase and the longest grains. The corrosion resistance of the forged LZ91 alloy increased due to grain refinement that prevented further corrosion during the immersion test. Among the experimental alloys, FR-LZ91 showed the highest resistance of corrosion film and charge transfer resistance values due to its protective film caused by the high area fraction of the β-Li phase.
The effect of rolling and forging on the microstructure and corrosion behavior of LZ91 alloy was investigated using an electron probe micro-analyzer, immersion and electrochemical tests. Results showed that the area fraction of the β-Li phase remained unchanged, and the grain size of the β-Li phase decreased after forging. The as-rolled forged alloy (FR-LZ91) exhibited the highest area fraction of the β-Li phase and the longest grains. The corrosion resistance of the forged LZ91 alloy increased due to grain refinement that prevented further corrosion during the immersion test. Among the experimental alloys, FR-LZ91 showed the highest resistance of corrosion film and charge transfer resistance values due to its protective film caused by the high area fraction of the β-Li phase.
2023, vol. 30, no. 1, pp.
82-91.
https://doi.org/10.1007/s12613-022-2472-x
Abstract:
Two new low-alloyed Mg–2RE–0.8Mn–0.6Ca–0.5Zn (wt%, RE = Sm or Y) alloys are developed, which can be produced on an industrial scale via relatively high-speed extrusion. These two alloys are not only comparable to commercial AZ31 alloy in extrudability, but also have superior mechanical properties, especially in terms of yield strength (YS). The excellent extrudability is related to less coarse second-phase particles and high initial melting point of the two as-cast alloys. The high strength–ductility mainly comes from the formation of fine grains, nano-spaced submicron/nano precipitates, and weak texture. Moreover, it is worth noting that the YS of the two alloys can maintain above 160 MPa at elevated temperature of 250°C, significantly higher than that of AZ31 alloy (YS: 45 MPa). The Zn/Ca solute segregation at grain boundaries, the improved heat resistance of matrix due to addition of RE, and the high melting points of strengthening particles (Mn, MgZn2, and Mg–Zn–RE/Mg–Zn–RE–Ca) are mainly responsible for the excellent high-temperature strength.
Two new low-alloyed Mg–2RE–0.8Mn–0.6Ca–0.5Zn (wt%, RE = Sm or Y) alloys are developed, which can be produced on an industrial scale via relatively high-speed extrusion. These two alloys are not only comparable to commercial AZ31 alloy in extrudability, but also have superior mechanical properties, especially in terms of yield strength (YS). The excellent extrudability is related to less coarse second-phase particles and high initial melting point of the two as-cast alloys. The high strength–ductility mainly comes from the formation of fine grains, nano-spaced submicron/nano precipitates, and weak texture. Moreover, it is worth noting that the YS of the two alloys can maintain above 160 MPa at elevated temperature of 250°C, significantly higher than that of AZ31 alloy (YS: 45 MPa). The Zn/Ca solute segregation at grain boundaries, the improved heat resistance of matrix due to addition of RE, and the high melting points of strengthening particles (Mn, MgZn2, and Mg–Zn–RE/Mg–Zn–RE–Ca) are mainly responsible for the excellent high-temperature strength.
2023, vol. 30, no. 1, pp.
92-103.
https://doi.org/10.1007/s12613-021-2388-x
Abstract:
We investigated the asymmetric tension–compression (T–C) behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests. The results show that the yield strengths of bars having bimodal structure are 206.42 and 140.28 MPa under tension and compression, respectively, which are higher than those of bars having uniform structure with tensile and compressive yield strength of 183.71 and 102.86 MPa, respectively. Prismatic slip and extension twinning under tension and basal slip and extension twinning under compression dominate the yield behavior and induce the T–C asymmetry. However, due to the basal slip activated in fine grains under tension and the inhibition of extension twinning by fine grains under compression, the bimodal structure possesses a lower T–C asymmetry (0.68) compared to the uniform structure (0.56). Multiple extension twins occur during deformation, and the selection of twin variants depends on the Schmid factor of the six variants activated by parent grains. Furthermore, the strengthening effect of the bimodal structure depends on the grain size and the ratio of coarse and fine grains.
We investigated the asymmetric tension–compression (T–C) behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests. The results show that the yield strengths of bars having bimodal structure are 206.42 and 140.28 MPa under tension and compression, respectively, which are higher than those of bars having uniform structure with tensile and compressive yield strength of 183.71 and 102.86 MPa, respectively. Prismatic slip and extension twinning under tension and basal slip and extension twinning under compression dominate the yield behavior and induce the T–C asymmetry. However, due to the basal slip activated in fine grains under tension and the inhibition of extension twinning by fine grains under compression, the bimodal structure possesses a lower T–C asymmetry (0.68) compared to the uniform structure (0.56). Multiple extension twins occur during deformation, and the selection of twin variants depends on the Schmid factor of the six variants activated by parent grains. Furthermore, the strengthening effect of the bimodal structure depends on the grain size and the ratio of coarse and fine grains.
2023, vol. 30, no. 1, pp.
104-111.
https://doi.org/10.1007/s12613-022-2550-0
Abstract:
The potential difference between positive and negative ions was utilized to improve the homogenized dispersion of nanoscale Al2O3 whiskers in Mg matrix composites. The Mg powders were decorated with sodium dodecylbenzene sulfonate (C18H29NaO3S, SDBS) and were introduced to the cathode group on their surface. The Al2O3 whiskers were modified by the cetyl trimethyl ammonium bromide (C19H42BrN, CTAB) and were featured in the anode group. The suitable contents of CTAB and SDBS, the application atmosphere, and the type of solvents were investigated. Dispersion results showed that adding 2wt% SDBS into Mg powders and adding 2wt% CTAB into Al2O3 whiskers promoted the formation of more uniformly mixed composite powders, compared to those of conventional ball milling via scanning electron microscopy (SEM) analysis. Meanwhile, the calculated results derived from first-principle calculations also demonstrated the stronger cohesion between Al2O3 whisker reinforcements and Mg matrix than undecorated composite powders. After preparation by powder metallurgy, the morphology, grain size, hardness, and standard deviation coefficient of composites were analyzed to evaluate the dispersed efficiency. The results indicated that the modification of homogenized dispersed Al2O3 whiskers in composites contributed to the refinement of 26% in grain size and the improvement of 20% in hardness compared with pure Mg, and the reduction of 32.5% in the standard deviation coefficient of hardness compared with the ball-milling sample.
The potential difference between positive and negative ions was utilized to improve the homogenized dispersion of nanoscale Al2O3 whiskers in Mg matrix composites. The Mg powders were decorated with sodium dodecylbenzene sulfonate (C18H29NaO3S, SDBS) and were introduced to the cathode group on their surface. The Al2O3 whiskers were modified by the cetyl trimethyl ammonium bromide (C19H42BrN, CTAB) and were featured in the anode group. The suitable contents of CTAB and SDBS, the application atmosphere, and the type of solvents were investigated. Dispersion results showed that adding 2wt% SDBS into Mg powders and adding 2wt% CTAB into Al2O3 whiskers promoted the formation of more uniformly mixed composite powders, compared to those of conventional ball milling via scanning electron microscopy (SEM) analysis. Meanwhile, the calculated results derived from first-principle calculations also demonstrated the stronger cohesion between Al2O3 whisker reinforcements and Mg matrix than undecorated composite powders. After preparation by powder metallurgy, the morphology, grain size, hardness, and standard deviation coefficient of composites were analyzed to evaluate the dispersed efficiency. The results indicated that the modification of homogenized dispersed Al2O3 whiskers in composites contributed to the refinement of 26% in grain size and the improvement of 20% in hardness compared with pure Mg, and the reduction of 32.5% in the standard deviation coefficient of hardness compared with the ball-milling sample.
2023, vol. 30, no. 1, pp.
112-121.
https://doi.org/10.1007/s12613-022-2428-1
Abstract:
First principles calculations and scanning Kelvin probe force microscopy (SKPFM) were used to investigate the effect of elements migration of α-AlFeMnSi phase on micro-galvanic corrosion behavior of Al–Zn–Mg alloy. The simulation results showed that the average work function difference between the α-AlFeMnSi phase and Al matrix decreased from 0.232 to 0.065 eV due to the synchronous migration of elements Fe–Mn–Si. Specifically, as the elements Fe–Si migration during the extrusion process, the average Volta potential difference detected by SKPFM between the α-AlFeMnSi phase and Al matrix dropped down to 432.383 mV from 648.370 mV. Thus, the elements migration reduced the micro-galvanic corrosion sensitivity of Al–Zn–Mg alloy. To reach the calculated low micro-galvanic tendency between α-AlFeMnSi phase and Al matrix, the diffusion of Mn should be promoted during extruding process.
First principles calculations and scanning Kelvin probe force microscopy (SKPFM) were used to investigate the effect of elements migration of α-AlFeMnSi phase on micro-galvanic corrosion behavior of Al–Zn–Mg alloy. The simulation results showed that the average work function difference between the α-AlFeMnSi phase and Al matrix decreased from 0.232 to 0.065 eV due to the synchronous migration of elements Fe–Mn–Si. Specifically, as the elements Fe–Si migration during the extrusion process, the average Volta potential difference detected by SKPFM between the α-AlFeMnSi phase and Al matrix dropped down to 432.383 mV from 648.370 mV. Thus, the elements migration reduced the micro-galvanic corrosion sensitivity of Al–Zn–Mg alloy. To reach the calculated low micro-galvanic tendency between α-AlFeMnSi phase and Al matrix, the diffusion of Mn should be promoted during extruding process.
2023, vol. 30, no. 1, pp.
122-130.
https://doi.org/10.1007/s12613-021-2349-4
Abstract:
The Shima yield criterion used in finite element analysis for nickel-based superalloy powder compact during hot isostatic pressing (HIP) was modified through uniaxial compression experiments. The influence of cylindrical capsule characteristics on FGH4096M superalloy powder compact deformation and densification behavior during HIP was investigated through simulations and experiments. Results revealed the simulation shrinkage prediction fitted well with the experimental shrinkage including a maximum shrinkage error of 1.5%. It was shown that the axial shrinkage was 1.7% higher than radial shrinkage for a cylindrical capsule with the size of ϕ50 mm × 100 mm due to the force arm difference along the axial and radial direction of the capsule. The stress deviated from the isostatic state in the capsule led to the uneven shrinkage and non-uniform densification of the powder compact. The ratio of the maximum radial displacement to axial displacement increased from 0.47 to 0.75 with the capsule thickness increasing from 2 to 4 mm. The pressure transmission is related to the capsule thickness, the capsule material performance, and physical parameters in the HIP process.
The Shima yield criterion used in finite element analysis for nickel-based superalloy powder compact during hot isostatic pressing (HIP) was modified through uniaxial compression experiments. The influence of cylindrical capsule characteristics on FGH4096M superalloy powder compact deformation and densification behavior during HIP was investigated through simulations and experiments. Results revealed the simulation shrinkage prediction fitted well with the experimental shrinkage including a maximum shrinkage error of 1.5%. It was shown that the axial shrinkage was 1.7% higher than radial shrinkage for a cylindrical capsule with the size of ϕ50 mm × 100 mm due to the force arm difference along the axial and radial direction of the capsule. The stress deviated from the isostatic state in the capsule led to the uneven shrinkage and non-uniform densification of the powder compact. The ratio of the maximum radial displacement to axial displacement increased from 0.47 to 0.75 with the capsule thickness increasing from 2 to 4 mm. The pressure transmission is related to the capsule thickness, the capsule material performance, and physical parameters in the HIP process.
2023, vol. 30, no. 1, pp.
131-143.
https://doi.org/10.1007/s12613-021-2387-y
Abstract:
Foreign body reactions to the wear debris and corrosion products from the implants, and bacterial infections are the main factors leading to the implant failures. In order to resolve these problems, the antibacterial TiN/Cu nanocomposite coatings with various N2 partial pressures were deposited on 304 stainless steels (SS) using an arc ion plating (AIP) system, named TiN/Cu-x (x = 0.5, 1.0, 1.5 Pa). The results of X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, and scanning electron microscopy showed that the N2 partial pressures determined the Cu contents, surface defects, and crystallite sizes of TiN/Cu nanocomposite coatings, which further influenced the comprehensive abilities. And the hardness and wear resistances of TiN/Cu coatings were enhanced with increase of the crystallite sizes. Under the co-actions of surface defects, crystallite sizes, and Cu content, TiN/Cu-1.0 and TiN/Cu-1.5 coatings possessed excellent corrosion resistance. Besides, the biological tests proved that all the TiN/Cu coatings showed no cytotoxicity with strong antibacterial ability. Among them, TiN/Cu-1.5 coating significantly promoted the cell proliferation, which is expected to be a novel antibacterial, corrosion-resistant, and wear-resistant coating on the surfaces of medical implants.
Foreign body reactions to the wear debris and corrosion products from the implants, and bacterial infections are the main factors leading to the implant failures. In order to resolve these problems, the antibacterial TiN/Cu nanocomposite coatings with various N2 partial pressures were deposited on 304 stainless steels (SS) using an arc ion plating (AIP) system, named TiN/Cu-x (x = 0.5, 1.0, 1.5 Pa). The results of X-ray diffraction analysis, energy-dispersive X-ray spectroscopy, and scanning electron microscopy showed that the N2 partial pressures determined the Cu contents, surface defects, and crystallite sizes of TiN/Cu nanocomposite coatings, which further influenced the comprehensive abilities. And the hardness and wear resistances of TiN/Cu coatings were enhanced with increase of the crystallite sizes. Under the co-actions of surface defects, crystallite sizes, and Cu content, TiN/Cu-1.0 and TiN/Cu-1.5 coatings possessed excellent corrosion resistance. Besides, the biological tests proved that all the TiN/Cu coatings showed no cytotoxicity with strong antibacterial ability. Among them, TiN/Cu-1.5 coating significantly promoted the cell proliferation, which is expected to be a novel antibacterial, corrosion-resistant, and wear-resistant coating on the surfaces of medical implants.
2023, vol. 30, no. 1, pp.
144-155.
https://doi.org/10.1007/s12613-022-2551-z
Abstract:
The need for reducing the wear in mechanical parts used in the industry makes self-lubricant films one of the sustainable solutions to achieve long-term protection under different environmental conditions. The purpose of this work is to study the influence of C additions on the tribological behavior of a magnetron-sputtered TiN film in air, water, and seawater. The results show that the addition of C into the TiN binary film induced a new amorphous phase, and the films exhibited a dual phase of fcc (face-centered cubic)-TiN and amorphous carbon. The antifriction and wear-resistance properties were enhanced in air and water by adding 19.1at% C. However, a further increase in the C concentration improved anti-frictional properties but also led to higher wear rates. Although the amorphous phase induced microbatteries and accelerated the corrosion of TiN phases in seawater, the negative abrasion state was detected for all Ti–C–N films due to the adhesion of the tribocorrosion debris on the wear track.
The need for reducing the wear in mechanical parts used in the industry makes self-lubricant films one of the sustainable solutions to achieve long-term protection under different environmental conditions. The purpose of this work is to study the influence of C additions on the tribological behavior of a magnetron-sputtered TiN film in air, water, and seawater. The results show that the addition of C into the TiN binary film induced a new amorphous phase, and the films exhibited a dual phase of fcc (face-centered cubic)-TiN and amorphous carbon. The antifriction and wear-resistance properties were enhanced in air and water by adding 19.1at% C. However, a further increase in the C concentration improved anti-frictional properties but also led to higher wear rates. Although the amorphous phase induced microbatteries and accelerated the corrosion of TiN phases in seawater, the negative abrasion state was detected for all Ti–C–N films due to the adhesion of the tribocorrosion debris on the wear track.
2023, vol. 30, no. 1, pp.
156-165.
https://doi.org/10.1007/s12613-022-2547-8
Abstract:
At present, iron and steel enterprises mainly use “after spot test ward” to control final product quality. However, it is impossible to realize on-line quality predetermining for all products by this traditional approach, hence claims and returns often occur, resulting in major economic losses of enterprises. In order to realize the on-line quality predetermining for steel products during manufacturing process, the prediction models of mechanical properties based on deep learning have been proposed in this work. First, the mechanical properties of deep drawing steels were predicted by using LSTM (long short team memory), GRU (gated recurrent unit) network, and GPR (Gaussian process regression) model, and prediction accuracy and learning efficiency for different models were also discussed. Then, on-line re-learning methods for transfer learning models and model parameters were proposed. The experimental results show that not only the prediction accuracy of optimized transfer learning models has been improved, but also predetermining time was shortened to meet real time requirements of on-line property predetermining. The industrial production data of interstitial-free (IF) steel was used to demonstrate that R2 value of GRU model in training stage reaches more than 0.99, and R2 value in testing stage is more than 0.96.
At present, iron and steel enterprises mainly use “after spot test ward” to control final product quality. However, it is impossible to realize on-line quality predetermining for all products by this traditional approach, hence claims and returns often occur, resulting in major economic losses of enterprises. In order to realize the on-line quality predetermining for steel products during manufacturing process, the prediction models of mechanical properties based on deep learning have been proposed in this work. First, the mechanical properties of deep drawing steels were predicted by using LSTM (long short team memory), GRU (gated recurrent unit) network, and GPR (Gaussian process regression) model, and prediction accuracy and learning efficiency for different models were also discussed. Then, on-line re-learning methods for transfer learning models and model parameters were proposed. The experimental results show that not only the prediction accuracy of optimized transfer learning models has been improved, but also predetermining time was shortened to meet real time requirements of on-line property predetermining. The industrial production data of interstitial-free (IF) steel was used to demonstrate that R2 value of GRU model in training stage reaches more than 0.99, and R2 value in testing stage is more than 0.96.
2023, vol. 30, no. 1, pp.
166-176.
https://doi.org/10.1007/s12613-022-2508-2
Abstract:
The reliable welding of T91 heat-resistant steel to 316L stainless steel is a considerable issue for ensuring the safety in service of ultra-supercritical power generation unit and nuclear fusion reactor, but the high-quality dissimilar joint of these two steels was difficult to be obtained by traditional fusion welding methods. Here we improved the structure–property synergy in a dissimilar joint of T91 steel to 316L steel via friction stir welding. A defect-free joint with a large bonding interface was produced using a small-sized tool under a relatively high welding speed. The bonding interface was involved in a mixing zone with both mechanical mixing and metallurgical bonding. No obvious material softening was detected in the joint except a negligible hardness decline of only HV ~10 in the heat-affected zone of the T91 steel side due to the formation of ferrite phase. The welded joint exhibited an excellent ultimate tensile strength as high as that of the 316L parent metal and a greatly enhanced yield strength on account of the dependable bonding and material renovation in the weld zone. This work recommends a promising technique for producing high-strength weldments of dissimilar nuclear steels.
The reliable welding of T91 heat-resistant steel to 316L stainless steel is a considerable issue for ensuring the safety in service of ultra-supercritical power generation unit and nuclear fusion reactor, but the high-quality dissimilar joint of these two steels was difficult to be obtained by traditional fusion welding methods. Here we improved the structure–property synergy in a dissimilar joint of T91 steel to 316L steel via friction stir welding. A defect-free joint with a large bonding interface was produced using a small-sized tool under a relatively high welding speed. The bonding interface was involved in a mixing zone with both mechanical mixing and metallurgical bonding. No obvious material softening was detected in the joint except a negligible hardness decline of only HV ~10 in the heat-affected zone of the T91 steel side due to the formation of ferrite phase. The welded joint exhibited an excellent ultimate tensile strength as high as that of the 316L parent metal and a greatly enhanced yield strength on account of the dependable bonding and material renovation in the weld zone. This work recommends a promising technique for producing high-strength weldments of dissimilar nuclear steels.
2023, vol. 30, no. 1, pp.
177-191.
https://doi.org/10.1007/s12613-022-2473-9
Abstract:
TiO2 is the dominant and most widely researched photocatalyst for environmental remediation, however, the drawbacks, such as only responding to UV light (<5% of sunlight), low charge separation efficiency, and difficulties in recycling, have severely hindered its practical application. Herein, we synthesized magnetically separable Fe3O4@MoS2@mesoporous TiO2 (FMmT) photocatalysts via a simple, green, and template-free solvothermal method combined with ultrasonic hydrolysis. It is found that FMmT possesses a high specific surface area (55.09 m2·g−1), enhanced visible-light responsiveness (~521 nm), and remarkable photogenerated charge separation efficiency. In addition, the photocatalytic degradation efficiencies of FMmT for methylene blue (MB), rhodamine B (RhB), and tetracycline (TC) are 99.4%, 98.5%, and 89.3% within 300 min, respectively. The corresponding degradation rates are 4.5, 4.3, and 3.1 times higher than those of pure TiO2 separately. Owing to the high saturation magnetization (43.1 A·m2·kg−1), FMmT can achieve effective recycling with an applied magnetic field. The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS2 and the electron–hole separation caused by the MoS2@TiO2 heterojunction. Meanwhile, the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO2 shell further boost the photocatalytic efficiency of FMmT. This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell.
TiO2 is the dominant and most widely researched photocatalyst for environmental remediation, however, the drawbacks, such as only responding to UV light (<5% of sunlight), low charge separation efficiency, and difficulties in recycling, have severely hindered its practical application. Herein, we synthesized magnetically separable Fe3O4@MoS2@mesoporous TiO2 (FMmT) photocatalysts via a simple, green, and template-free solvothermal method combined with ultrasonic hydrolysis. It is found that FMmT possesses a high specific surface area (55.09 m2·g−1), enhanced visible-light responsiveness (~521 nm), and remarkable photogenerated charge separation efficiency. In addition, the photocatalytic degradation efficiencies of FMmT for methylene blue (MB), rhodamine B (RhB), and tetracycline (TC) are 99.4%, 98.5%, and 89.3% within 300 min, respectively. The corresponding degradation rates are 4.5, 4.3, and 3.1 times higher than those of pure TiO2 separately. Owing to the high saturation magnetization (43.1 A·m2·kg−1), FMmT can achieve effective recycling with an applied magnetic field. The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS2 and the electron–hole separation caused by the MoS2@TiO2 heterojunction. Meanwhile, the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO2 shell further boost the photocatalytic efficiency of FMmT. This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell.
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