H-2 absorbing-desorbing characterization of the Ti-V-Fe alloy system

Twenty six kinds of alloys with compositions Ti(33-47 mol%)-V(42-67 mol%)-Fe(0-14 mol%) were tested to find the most suitable composition for hydrogen absorbtion (including tritium recovery and storage). The best alloy composition was found to be Ti43.5V49.0Fe7.5, and this alloy was able to absorb hydrogen up to 3.90 wt% (H/M = 1.90) at 253 K. The hydrogen capacity was estimated to be 2.4 wt% when hydrogen was absorbed at 253 K and desorbed at 573 K at 1 atm hydrogen pressure. The hydrogen absorption rate at 253 K was faster than that of the LaNi5-H-2 system at 293 K. Conspicuous changes in pressure-composition (p-c) isotherms were not found after 50 cycles of hydrogen absorption and desorption. All dehydrided alloys are bcc, dihydrides of the alloy are fee. Among the series of Ti-V-X alloys (X = Fe, Co, Ni, Cr and Pd), iron was found to be the best substituent element for X. Two kinds of industrial ferrovanadium alloys containing about 4 wt% of impurities (Al, Si, etc.) were tested to prepare the alloys. Remarkable differences in the p-c isotherms were observed which may be due to the effect of impurities in the ferrovanadium.