The influence of ball milling process on hydrogenation properties of MgH2–FeTiHx composites

In this work, the MgH2–FeTiHx composites were synthesized in a wide range of compositions by reactive mechanical milling. The phase structure and morphology were investigated by XRD and SEM. The hydrogen desorption characteristics of obtained composites were measured by a volumetric method using Sievert's apparatus. It is demonstrated that the hydrogen desorption kinetics in the magnesium-intermetallic hydride composites is affected not only by the phase composition but also by the milling parameters. The particle size of composite constituents is slightly related to the amount of additive and strongly to milling time. The exponential factor in Johnson–Mehl–Avrami's equation decreases for composite powders in comparison to reference MgH2 from ∼2 to ∼1. Our results clearly show that there is a considerable catalytic effect of the FeTi additive on the hydrogen absorption and desorption kinetics. The energy of activation for both processes decreases in visible way for MgH2 catalyzed by 50 wt.% of FeTiHx hydride.