Studies on the hydrogen absorption/desorption properties of Zr(1-x)Mm(x)Fe(1.4)Cr(0.6) and Zr(1-2x)Mm(x)Ti(x)Fe(1.4)Cr(0.6) (X=0, 0.05, 0.1 and 0.2) Laves phase alloys

The Mm, Ti-substituted Zr(1-2x)Mm(x)Ti(x)Fe(1.4)Cr(0.6) (x = 0, 0.05, 0.1 a nd 0.2) Laves phase alloys show high hydrogen storage capacity of similar t o1.75 wt% and kinetics of similar to 30 cm(3) min(-1) g(-1) which is 3 time s faster than the parent alloy ZrFe1.4Cr0.6. High hydrogen storage capacity is observed for small concentrations of Mm (x = 0.03-0.07). The best stora ge materials correspond to the composition of x = 0.05. Eventhough the Mm-s ubstituted Laves phase alloys Zr(1-x)Mm(x)Cr(1.4)Cr(0.6) (x = 0, 0.05, 0.1 and 0.2) have high capacity of 1.6 wt%, their kinetics is rather poor (< 10 cm(3) min(-1) g(-1)). The high hydrogen storage capacity and fast kinetics of Mm, Ti-substituted alloys are attributed to disorder/defects introduced as evidenced through XRD, SEM and TEM studies. (C) 2001 Published by Elsev ier Science Ltd on behalf of the International Association for Hydrogen Ene rgy.