The environmental embrittlement of intermetallics Co3Ti, Ni3Al, Fe3Al and TiAl has been investigated by measuring the tensile properties in oxygen and hydrogen at 2×l0-4/s strain rate. The results show that the ...The environmental embrittlement of intermetallics Co3Ti, Ni3Al, Fe3Al and TiAl has been investigated by measuring the tensile properties in oxygen and hydrogen at 2×l0-4/s strain rate. The results show that the hydrogen embrittlement factor in gaseous hydrogen (IH2 ) defined as[(δO2 -δH2 ) / δH2, ] ×l00% of above mentioned four intermetallics is decreased in the sequence of Co3Ti> Ni3Al> Fe3Al> TiAl. This phenomena can be explained by the different catalytic reaction on the surface of matrix metals (such as Ni, Co, Fe, Ti) with decomposition of H2 into atommic hydrogen, leading to hydrogen embrittlement.展开更多
The effect of boron doping on the sensitivity to environmental embrittlement of Ni3Al-based alloys was investigated in this paper. The results show that the ductilizing effect of boron in Ni3Al is partly to suppress ...The effect of boron doping on the sensitivity to environmental embrittlement of Ni3Al-based alloys was investigated in this paper. The results show that the ductilizing effect of boron in Ni3Al is partly to suppress moisture-induced hydrogen embrittlement.The mechanism of this suppressing effect of boron relates to its severely decreasing the hydrogen diffusivity by boron segregated at the grain boundaries. The surface reaction of Fe3Al with water vapor and oxygen was experimentally confirmed by AES and XPS analysis. The kinetics of these reactions can be used to explain the different ductility behavior of aluminides in various environments.展开更多
Porous intermetallics show potential in the field of filtration and separation as well as in the field of catalysis.Herein,porous Ti Fe2intermetallics were fabricated by the reactive synthesis of elemental powders.The...Porous intermetallics show potential in the field of filtration and separation as well as in the field of catalysis.Herein,porous Ti Fe2intermetallics were fabricated by the reactive synthesis of elemental powders.The phase transformation and pore formation of porous TiFe2intermetallics were investigated,and its corrosion behavior and hydrogen evolution reaction(HER)performance in alkali solution were studied.Porous TiFe2intermetallics with porosity in the range of 34.4%-56.4%were synthesized by the diffusion reaction of Ti and Fe elements,and the pore formation of porous TiFe2intermetallic compound is the result of a combination of the bridging effect and the Kirkendall effect.The porous TiFe2samples exhibit better corrosion resistance compared with porous 316L stainless steel,which is related to the formation of uniform nanosheets on the surface that hinder further corrosion,and porous TiFe2electrode shows the overpotential of 220.6 and 295.6 mV at 10 and 100 mA·cm-2,suggesting a good catalytic performance.The synthesized porous Fe-based intermetallic has a controllable pore structure as well as excellent corrosion resistance,showing its potential in the field of filtration and separation.展开更多
Ordered mesoporous noble metals(NMs)have displayed unique catalytic and electrocatalytic performance distinctive from traditional nanoparticles.Despite great efforts,the range of mesoporous NMs is mainly limited to si...Ordered mesoporous noble metals(NMs)have displayed unique catalytic and electrocatalytic performance distinctive from traditional nanoparticles.Despite great efforts,the range of mesoporous NMs is mainly limited to single metals and their metal alloys with random atomic arrangements.Herein,we report a simple solid-phase synthesis of novel mesoporous intermetallic noble metal-nonmetal(MI-PtX_(2))nanoparticles with hierarchical orderliness as highly efficient electrocatalysts for hydrogen evolution reaction(HER).The synthesis relies on a Pt-to-PtX_(2) evolution with mesoporous Pt confined in thermally stable KIT-6(Korea Advanced Institute of Science and Technology-6)as the concurrent template.Meanwhile,the method could be extended readily to control structures and compositions of mesoporous intermetallic nanoparticles such as hollow structures and ternary MI-PtMP_(2).Samples featured rhombic dodecahedral morphology,ordered gyroid mesostructure,and cubic/hexagonal intermetallic phase,producing abundant undercoordinated sites and optimized surface electronic structures.These features kinetically accelerate H_(2)O dissociation to remarkably enhance electrocatalytic HER performance.The optimum MI-PtP_(2) disclosed ultrahigh mass/specific activity(3.31 A mg_(pt)^(−1)/7.75 mA cm_(pt)^(−2))and superior stability(only 15.2%of mass activity loss after an accelerated durability test for 30,000 cycles),suppressing the reported electrocatalysts.Our work opens up new opportunities for designing and synthesizing novel hierarchically ordered mesoporous electrocatalysts with targeted functions for a variety of applications.展开更多
文摘The environmental embrittlement of intermetallics Co3Ti, Ni3Al, Fe3Al and TiAl has been investigated by measuring the tensile properties in oxygen and hydrogen at 2×l0-4/s strain rate. The results show that the hydrogen embrittlement factor in gaseous hydrogen (IH2 ) defined as[(δO2 -δH2 ) / δH2, ] ×l00% of above mentioned four intermetallics is decreased in the sequence of Co3Ti> Ni3Al> Fe3Al> TiAl. This phenomena can be explained by the different catalytic reaction on the surface of matrix metals (such as Ni, Co, Fe, Ti) with decomposition of H2 into atommic hydrogen, leading to hydrogen embrittlement.
文摘The effect of boron doping on the sensitivity to environmental embrittlement of Ni3Al-based alloys was investigated in this paper. The results show that the ductilizing effect of boron in Ni3Al is partly to suppress moisture-induced hydrogen embrittlement.The mechanism of this suppressing effect of boron relates to its severely decreasing the hydrogen diffusivity by boron segregated at the grain boundaries. The surface reaction of Fe3Al with water vapor and oxygen was experimentally confirmed by AES and XPS analysis. The kinetics of these reactions can be used to explain the different ductility behavior of aluminides in various environments.
基金financially supported by the National Natural Science Foundation of China(No.51971251)。
文摘Porous intermetallics show potential in the field of filtration and separation as well as in the field of catalysis.Herein,porous Ti Fe2intermetallics were fabricated by the reactive synthesis of elemental powders.The phase transformation and pore formation of porous TiFe2intermetallics were investigated,and its corrosion behavior and hydrogen evolution reaction(HER)performance in alkali solution were studied.Porous TiFe2intermetallics with porosity in the range of 34.4%-56.4%were synthesized by the diffusion reaction of Ti and Fe elements,and the pore formation of porous TiFe2intermetallic compound is the result of a combination of the bridging effect and the Kirkendall effect.The porous TiFe2samples exhibit better corrosion resistance compared with porous 316L stainless steel,which is related to the formation of uniform nanosheets on the surface that hinder further corrosion,and porous TiFe2electrode shows the overpotential of 220.6 and 295.6 mV at 10 and 100 mA·cm-2,suggesting a good catalytic performance.The synthesized porous Fe-based intermetallic has a controllable pore structure as well as excellent corrosion resistance,showing its potential in the field of filtration and separation.
文摘Ordered mesoporous noble metals(NMs)have displayed unique catalytic and electrocatalytic performance distinctive from traditional nanoparticles.Despite great efforts,the range of mesoporous NMs is mainly limited to single metals and their metal alloys with random atomic arrangements.Herein,we report a simple solid-phase synthesis of novel mesoporous intermetallic noble metal-nonmetal(MI-PtX_(2))nanoparticles with hierarchical orderliness as highly efficient electrocatalysts for hydrogen evolution reaction(HER).The synthesis relies on a Pt-to-PtX_(2) evolution with mesoporous Pt confined in thermally stable KIT-6(Korea Advanced Institute of Science and Technology-6)as the concurrent template.Meanwhile,the method could be extended readily to control structures and compositions of mesoporous intermetallic nanoparticles such as hollow structures and ternary MI-PtMP_(2).Samples featured rhombic dodecahedral morphology,ordered gyroid mesostructure,and cubic/hexagonal intermetallic phase,producing abundant undercoordinated sites and optimized surface electronic structures.These features kinetically accelerate H_(2)O dissociation to remarkably enhance electrocatalytic HER performance.The optimum MI-PtP_(2) disclosed ultrahigh mass/specific activity(3.31 A mg_(pt)^(−1)/7.75 mA cm_(pt)^(−2))and superior stability(only 15.2%of mass activity loss after an accelerated durability test for 30,000 cycles),suppressing the reported electrocatalysts.Our work opens up new opportunities for designing and synthesizing novel hierarchically ordered mesoporous electrocatalysts with targeted functions for a variety of applications.
