Iranian Journal of Materials Science and Engineering

In this study, the composite material with composition of MgH₂-5 wt% SiC has been prepared by co-milling of MgH₂ with SiC powder. The effect of milling time and additive on MgH₂ structure, i.e. crystallite size, lattice strain, particle size and specific surface area, and also hydrogen desorption properties of obtained composite was evaluated by thermal analyzer method and compared with pure un-milled MgH₂. The phase constituents and grain size of powder were characterized by X-ray diffractometry method. It has been shown that addition of 5 wt% SiC to MgH₂ and mechanical alloying up to 30 h formed a nanocrystalline composite with the average crystallite size of 12 nm, average particle size of 0.5 µm and specific surface area of 10 m²/g. On the other hand, SiC can help to break up particles and reduce the particle size. As a consequence, the desorption temperature of composite material milled for 30 h has decreased from 435 °C to 361 °C.