Correlation between hydrogen absorption properties and homogeneity of Ti–Cr–V alloys

The factor affecting the hydrogen storage capacity of Ti–Cr–V b.c.c. solid solution alloys was investigated and a method to increase the capacity was proposed. The concentration of each element of the Ti–Cr–V alloy did not become very uniform by the heat treatment. The degree of fluctuation in vanadium concentration between higher and lower vanadium area content exceeds 5 wt.%, even after the conventional heat treatment. But we successfully made a more homogeneous alloy by the application of the floating zone (FZ) melting process. The degree of fluctuation in the vanadium concentration in this alloy diminished to under 2.5 wt.%. The flatness of the plateau and the rechargeable hydrogen storage capacity were drastically improved by this homogenizing process. The rechargeable hydrogen storage capacity of FZ melted alloy reached 2.7 wt.%, although that of the heat-treated alloy remained at 2.1 wt.%. [Copyright &y& Elsevier]