Effect of Cr addition on room temperature hydrogenation of TiFe alloys

Abstract

This paper discusses the effect of AB2 (Ti(Cr, Fe)2) phase on the hydrogenation properties of a Ti–Fe–Cr alloy system. Five Ti–Fe–Cr based alloys were fabricated by varying the Cr content. The microstructural analysis results revealed that the fraction of the Ti(Cr, Fe)2 phase increased with the increasing Cr content. The first hydrogenation test results indicated that all the alloys could absorb a significant amount of hydrogen at room temperature (30 °C) without a separate activation process. This behavior improved when the Ti(Cr, Fe)2 phase existed in the AB phase; the kinetics of the first hydrogenation tended to increase with the fraction of Ti(Cr, Fe)2 phase. The enhancement in the first hydrogenation kinetics of the Ti–Fe–Cr based alloys was attributed to the synergetic effect of the interface between the AB and Ti(Cr, Fe)2 phases and the inherent fast hydrogenation of the Ti(Cr, Fe)2 phase. However, the total hydrogen storage capacity decreased when the fraction of Ti(Cr, Fe)2 phase increased.