Hydrogen sorption characteristics of the composites 90 wt.% Mg (MgH₂)–10 wt.% V_0.855Ti_0.095Fe_0.05

The hydrogen absorption–desorption characteristics of composites containing 90 wt.% Mg or MgH₂ and 10 wt.% of the intermetallic compound V_0.855Ti_0.095Fe_0.05 obtained by mechanical alloying for 1 and 5 h in an inert medium were investigated. Absorption measurements were performed under a hydrogen pressure P = 1 MPa at temperatures of 623, 573, 523, and 473 K. Dehydriding was studied at 623 and 573 K and a pressure of 0.15 MPa. It was established that the presence of the additive improved significantly the hydriding kinetics of magnesium while the effect of the duration of mechanical alloying was less pronounced. Due to the small difference in specific surface areas and crystallite sizes, both composites investigated showed no substantial difference in behavior during absorption and desorption of hydrogen. The best absorption–desorption properties were found with the composite 90 wt.% Mg–10 wt.% V_0.855Ti_0.095Fe_0.05 mechanically activated for 5 h.