La-Y-Ni alloys exhibit high discharge capacity due to the formation of AB_(3-3.8)-type(A=La,Y;B=Ni)intermetallic compounds.However,the stable composition and temperature range for this type of phase are rarely reporte...La-Y-Ni alloys exhibit high discharge capacity due to the formation of AB_(3-3.8)-type(A=La,Y;B=Ni)intermetallic compounds.However,the stable composition and temperature range for this type of phase are rarely reported,which restrains the development of La-Y-Ni hydrogen storage alloys with stable structure and high capacity.This paper focuses on the phase equilibria of the La-Y-Ni ternary system in Ni-rich corner.The phase constitution,microstructure,and equilibrated composition were experimentally determined at 1273 and 1148 K using X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy-dispersive spectroscopy(EDS).The solubilities of La and Y in the binary compounds were measured.Two ternary compounds,3R-LaY_(2)Ni_(9)with the structure of PuNi3 type and La_(0.5)Y_(0.5)Ni_(5)with the structure of CaCu5 type,existed at both temperatures.Based on the experimental data,the thermodynamic description of LaY-Ni system was assessed by Calculation of Phase Diagram method.The calculated isothermal sections agree with the experimental data.The thermodynamic database is helpful for the design of La-Y-Ni hydrogen storage alloys.展开更多
基金financially supported by the National Key R&D Program of China(No.2021YFB3502200)National Natural Science Foundation of China(No.51734002)+1 种基金Science and Technology Committee of Shanghai(Nos.19010500400 and 19DZ2252900)Shanghai Rising-Star Program(No.21QA1403200)。
文摘La-Y-Ni alloys exhibit high discharge capacity due to the formation of AB_(3-3.8)-type(A=La,Y;B=Ni)intermetallic compounds.However,the stable composition and temperature range for this type of phase are rarely reported,which restrains the development of La-Y-Ni hydrogen storage alloys with stable structure and high capacity.This paper focuses on the phase equilibria of the La-Y-Ni ternary system in Ni-rich corner.The phase constitution,microstructure,and equilibrated composition were experimentally determined at 1273 and 1148 K using X-ray diffraction(XRD),scanning electron microscopy(SEM),and energy-dispersive spectroscopy(EDS).The solubilities of La and Y in the binary compounds were measured.Two ternary compounds,3R-LaY_(2)Ni_(9)with the structure of PuNi3 type and La_(0.5)Y_(0.5)Ni_(5)with the structure of CaCu5 type,existed at both temperatures.Based on the experimental data,the thermodynamic description of LaY-Ni system was assessed by Calculation of Phase Diagram method.The calculated isothermal sections agree with the experimental data.The thermodynamic database is helpful for the design of La-Y-Ni hydrogen storage alloys.
