Effects of desorption temperature and substitution of Fe for Cr on the hydrogen storage properties of Ti0.32Cr0.43V0.25Ti0.32Cr0.43V0.25 alloy

A study was made on how desorption temperature affected the usable hydrogen of the Ti0.32Cr0.43V0.25 alloy. The temperature was varied from 303 to 423 K, and the pressure from 5 to 0.002 MPa. The usable hydrogen of the alloy was 2.63 wt% when absorbed and desorbed at 303 and 423 K, respectively. The heat of hydride formation of the alloy was approximately -38kJ/molH2. The effects of substituting Fe for Cr on the hydrogen storage property of the Ti0.32Cr0.43V0.25 alloy have also been studied. The purpose of the substitution was twofold: to raise the desorption plateau pressure of the alloy to 0.1 MPa or higher and to examine the possibility of using cheaper ferrovanadium. The logarithmic desorption plateau pressure increased linearly with the decrease of the lattice volume. When the Fe content was 8 at%, the desorption plateau pressure increased to several atmospheres without decrease in the effective hydrogen storage capacity of the alloy. This result suggested the possibility of using ferrovanadium as a substitute for the expensive pure vanadium.