Hydrogen storage characteristics of Ti1.04Fe0.7Ni0.1Zr0.1Mn0.1Pr0.06 alloy treated by ball milling

Abstract

In order to enhance the hydrogen storage performances of TiFe alloy, the Ti1.04Fe0.7Ni0.1Zr0.1Mn0.1Pr0.06 alloy was prepared through using transition metals (Ni, Mn, Zr) partially substitute Fe and rare earth Pr partially substitute Ti. The microstructure of the alloy was further adjusted by ball milling for different time. The master alloy contained TiFe, Ti2Fe and Pr phases. Ball milling treatment led to the reduction of the particle size and grain size. The master alloy (M-0 sample) and the alloys with short-time ball milling treatment (M-0.5 and M-1 samples) absorbed hydrogen immediately at the first hydrogenation cycle at 423 K and 3 MPa H2, while the alloys with long-time ball milling treatment (M-3 and M-5 samples) showed an incubation time. The M-0.5 sample not only presented the optimum activation property, but also showed the most outstanding hydriding/dehydriding kinetics and capacity. It achieved the saturated hydrogenation state within 2158 s. The hydrogenation capacity was 1.471, 1.626, 1.547, 1.485 and 1.417 wt% for the M-0, M-0.5, M-1, M-3 and M-5 samples at 313 K and 3 MPa H2, respectively. In addition, ball milling treatment caused the decrease of cell volume of TiFe phase in the samples, which reduced the thermodynamic stability of the hydrides.