Hydriding/dehydriding properties of Mg-Ni-based ternary alloys
synthesized by mechanical grinding
synthesized by mechanical grinding
(1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China)
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China)
Abstract: The Mg-Ni-based ternary alloys Mg2-xTixNi(x=0, 0.2, 0.4) and Mg2Ni1-xZrx(x=0, 0.2, 0.4) were successfully synthesized by mechanical grinding. The phases in the alloys and the hydriding/dehydriding properties of the alloys were investigated. Mg2Ni and Mg are the main hydrogen absorption phases in the alloys by XRD analysis. Hydriding kinetics curves of the alloys indicate that the hydrogen absorption rate increases after partial substitution of Ti for Mg and Zr for Ni. According to the measurement of pressure-concentration-isotherms and Van’t Hoff equation, the relationship between ln p(H2) and 1 000/T was established. It is found that while increasing the content of correspondingly substituted elements at the same temperature, the equilibrium pressure of dehydriding increases, the enthalpy change and the stability of the alloy hydride decrease.
Key words: Mg-Ni-based hydrogen storage alloy; mechanical grinding; p-C-T measurement; hydriding properties; enthalpy change