Degradation properties of hydrogen storage alloys and change of microstructure during the degradation

Ti-Cr-V alloys with body-centered cubic (BCC) structure were investigated on hydrogen absorbing-desorbing cyclic durability by using H-2 without and with several concentrations of CO (Hereafter, they are described as pure H-2 and n ppm CO, respectively.). The alloy which offers the excellent durability except the early stages of cyclic absorption-desorption under pure H-2 atmosphere gave good durability also in a flow of low concentration of CO. However, capacities' degradation curves under high CO concentration reflected that duration and concentration effects competed with each other. The results suggests to be able to express each degradation by intrinsic and extrinsic factors as an aggregation of several prime functions.