Exploring the effective way to improve Fe2 B's toughness has always been the hot topic in the researches of Fe-B wear resistant alloys.In the present work,the effects of Cr on the microstructure,mechanical propert...Exploring the effective way to improve Fe2 B's toughness has always been the hot topic in the researches of Fe-B wear resistant alloys.In the present work,the effects of Cr on the microstructure,mechanical properties and lattice structure of directional Fe2 B have been investigated.The affecting mechanism of Cr addition has been discussed according to the experimental and first-principle calculation analysis.The results show Cr addition can improve the toughness of directional Fe2 B on the longitudinal sections perpendicular to(002) crystal plane,without sacrificing the hardness distinctly.The toughening mechanism by Cr substitution has been revealed:Cr addition enriches the electron density between the B atoms along [002] direction,contributing to the shrinkage of the bond length and the enhancement of the bond strength of B-B bonds.The obtained results provide insight into the intrinsic reason for toughening Fe2 B by Cr doping.展开更多
回收利用是稀土资源高效利用的可持续方案.氢化破碎技术因其高效环保特性被广泛采用,但氢破过程中产生的混合相会显著降低回收效率,这对工艺的优化提出了新的挑战.本文采用基于第一性原理计算结合机器学习方法,通过德拜模型系统地探究...回收利用是稀土资源高效利用的可持续方案.氢化破碎技术因其高效环保特性被广泛采用,但氢破过程中产生的混合相会显著降低回收效率,这对工艺的优化提出了新的挑战.本文采用基于第一性原理计算结合机器学习方法,通过德拜模型系统地探究了氢化破碎过程中关键稀土氢化物(如NdH_(2),NdH_(3),Nd_(2)H_(5))的热力学行为.研究结果表明,在600 k Pa压强下,630 K左右的温度区间有望为氢化破碎工艺提供一个较为理想的操作条件.在此条件下,NdH_(2)能够实现自发氢化,且能够有效抑制非稳定相的形成,有助于提高稀土回收效率.本研究还揭示了过高温度对NdH_(2)热力学性质可能产生的不利影响,进一步强调了在特定温度区间操作的重要性.这些发现不仅为理解钕铁硼氢化过程的热力学机理提供了新的视角,而且为工业应用中氢化破碎工艺参数的优化提供了理论参考.展开更多
Herein,binary and ternary MOF/carbon based composites(MOF/Carbon nitride/Graphene oxide)(novel binary(NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4))(MOF/Carbon nitride)and ternary(NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4)/GO)(MOF/Carbon nitr...Herein,binary and ternary MOF/carbon based composites(MOF/Carbon nitride/Graphene oxide)(novel binary(NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4))(MOF/Carbon nitride)and ternary(NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4)/GO)(MOF/Carbon nitride/Graphene oxide)composites)were synthesized and used as photocatalysts for the elimination of Direct Red 23(D-Red23)and Tetracycline Hydrochloride(TC-H).NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4)/GO(MILB/g/GO)ternary composites with three different amounts of GO including 3,7,and 11 wt%were synthesized and denoted as MILB/g/(3%)GO,MILB/g/(7%)GO,and MILB/g/(11%)GO.g-C_(3)N_(4)and GO(with three different amounts 3,7,and 11 wt%)were incorporated to synthesize MILB/g/(3%)GO,MILB/g/(7%)GO and MILB/g/(11%)GO ternary composites.Several analyses were used to characterize the materials.The MILB/g/(3%)GO demonstrated the highest pollutant degradation efficiency.The degradation rate of dye and Tetracycline after 70 min of light radiation using MILB/g/(3%)GO in a photo-Fenton-like reaction was about 99%and 96%,respectively.The creation of a heterojunction structure using g-C_(3)N_(4),and the simultaneous incorporation of the optimum amount of GO led to a remarkable amelioration in photocatalytic properties and the extraordinary performance of MILB/g/(3%)GO in the pollutants degradation process.展开更多
The high cost of using the niobium(Nb)barrier for manufacturing magnesium diboride(MgB2)mono-and multi-filamentary wires for large-scale applications has become one of the barriers to replacing current commercial niob...The high cost of using the niobium(Nb)barrier for manufacturing magnesium diboride(MgB2)mono-and multi-filamentary wires for large-scale applications has become one of the barriers to replacing current commercial niobium-titanium superconductors.The potential of replacing the Nb barrier with a low-cost iron(Fe)barrier for multifilament MgB2 superconducting wires is investigated in this manuscript.Therefore,MgB2 wires with Fe barrier sintered with different temperatures are studied(from 650°C to 900°C for 1 h)to investigate the non-superconducting reaction phase of Fe-B.Their superconducting performance including engineering critical current density(Je)and n-value are tested at 4.2 K in various external magnetic fields.The best sample sintered at 650°C for 1 h has achieved a Je value of 3.64×10^(4) A cm^(−2) and an n-value of 61 in 2 T magnetic field due to the reduced formation of Fe2B,better grain connectivity and homogenous microstructure.For microstructural analysis,the focused ion beam(FIB)is utilised for the first time to acquire three-dimensional microstructures and elemental mappings of the interface between the Fe barrier and MgB2 core of different wires.The results have shown that if the sintering temperature can be controlled properly,the Je and n-value of the wire are still acceptable for magnet applications.The formation of Fe2B is identified along the edge of MgB2,as the temperature increases,the content of Fe2B also increases which causes the degradation in the performance of wires.展开更多
基金supported financially by the China Postdoctoral Science Foundation (No. 2019M663700)the Natural Science Foundation of Shaanxi Province (No. 2020JQ-056)the Fundamental Research Funds for the Central Universities, Xi’an Jiaotong University, China (No. sxxj022019024)。
文摘Exploring the effective way to improve Fe2 B's toughness has always been the hot topic in the researches of Fe-B wear resistant alloys.In the present work,the effects of Cr on the microstructure,mechanical properties and lattice structure of directional Fe2 B have been investigated.The affecting mechanism of Cr addition has been discussed according to the experimental and first-principle calculation analysis.The results show Cr addition can improve the toughness of directional Fe2 B on the longitudinal sections perpendicular to(002) crystal plane,without sacrificing the hardness distinctly.The toughening mechanism by Cr substitution has been revealed:Cr addition enriches the electron density between the B atoms along [002] direction,contributing to the shrinkage of the bond length and the enhancement of the bond strength of B-B bonds.The obtained results provide insight into the intrinsic reason for toughening Fe2 B by Cr doping.
文摘回收利用是稀土资源高效利用的可持续方案.氢化破碎技术因其高效环保特性被广泛采用,但氢破过程中产生的混合相会显著降低回收效率,这对工艺的优化提出了新的挑战.本文采用基于第一性原理计算结合机器学习方法,通过德拜模型系统地探究了氢化破碎过程中关键稀土氢化物(如NdH_(2),NdH_(3),Nd_(2)H_(5))的热力学行为.研究结果表明,在600 k Pa压强下,630 K左右的温度区间有望为氢化破碎工艺提供一个较为理想的操作条件.在此条件下,NdH_(2)能够实现自发氢化,且能够有效抑制非稳定相的形成,有助于提高稀土回收效率.本研究还揭示了过高温度对NdH_(2)热力学性质可能产生的不利影响,进一步强调了在特定温度区间操作的重要性.这些发现不仅为理解钕铁硼氢化过程的热力学机理提供了新的视角,而且为工业应用中氢化破碎工艺参数的优化提供了理论参考.
基金This manuscript is extracted from project(981179017)funded by Institute for Color Science and Technology.
文摘Herein,binary and ternary MOF/carbon based composites(MOF/Carbon nitride/Graphene oxide)(novel binary(NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4))(MOF/Carbon nitride)and ternary(NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4)/GO)(MOF/Carbon nitride/Graphene oxide)composites)were synthesized and used as photocatalysts for the elimination of Direct Red 23(D-Red23)and Tetracycline Hydrochloride(TC-H).NH_(2)-MIL-88B(Fe)/g-C_(3)N_(4)/GO(MILB/g/GO)ternary composites with three different amounts of GO including 3,7,and 11 wt%were synthesized and denoted as MILB/g/(3%)GO,MILB/g/(7%)GO,and MILB/g/(11%)GO.g-C_(3)N_(4)and GO(with three different amounts 3,7,and 11 wt%)were incorporated to synthesize MILB/g/(3%)GO,MILB/g/(7%)GO and MILB/g/(11%)GO ternary composites.Several analyses were used to characterize the materials.The MILB/g/(3%)GO demonstrated the highest pollutant degradation efficiency.The degradation rate of dye and Tetracycline after 70 min of light radiation using MILB/g/(3%)GO in a photo-Fenton-like reaction was about 99%and 96%,respectively.The creation of a heterojunction structure using g-C_(3)N_(4),and the simultaneous incorporation of the optimum amount of GO led to a remarkable amelioration in photocatalytic properties and the extraordinary performance of MILB/g/(3%)GO in the pollutants degradation process.
基金support from the Australian Research Council(ARC)Linkage Project(LP200200689).
文摘The high cost of using the niobium(Nb)barrier for manufacturing magnesium diboride(MgB2)mono-and multi-filamentary wires for large-scale applications has become one of the barriers to replacing current commercial niobium-titanium superconductors.The potential of replacing the Nb barrier with a low-cost iron(Fe)barrier for multifilament MgB2 superconducting wires is investigated in this manuscript.Therefore,MgB2 wires with Fe barrier sintered with different temperatures are studied(from 650°C to 900°C for 1 h)to investigate the non-superconducting reaction phase of Fe-B.Their superconducting performance including engineering critical current density(Je)and n-value are tested at 4.2 K in various external magnetic fields.The best sample sintered at 650°C for 1 h has achieved a Je value of 3.64×10^(4) A cm^(−2) and an n-value of 61 in 2 T magnetic field due to the reduced formation of Fe2B,better grain connectivity and homogenous microstructure.For microstructural analysis,the focused ion beam(FIB)is utilised for the first time to acquire three-dimensional microstructures and elemental mappings of the interface between the Fe barrier and MgB2 core of different wires.The results have shown that if the sintering temperature can be controlled properly,the Je and n-value of the wire are still acceptable for magnet applications.The formation of Fe2B is identified along the edge of MgB2,as the temperature increases,the content of Fe2B also increases which causes the degradation in the performance of wires.
