Progress in Combustion Synthesis of Metal Hydrides

摘要

Combustion synthesis, a new materials fabrication technology through self-sustainingreaction (without requiring additional heat), has recently been applied to the synthesisof metal hydrides and alloys for hydrogen storage. Compared with the conventionalroutes of casting and mechanical alloying, combustion synthesis not only offers a highefficiency, energy- and time-saving, and cost reduction process, but also cansynthesize a fully hydride product with low contamination without any activation. Themain characteristics and mechanisms of the combustion of pure metal powders suchas Ti, Nb, Zr, Y, and Hf, or the metal powder mixtures, for example, Ti and Mg, orMg and Ni, in an atmosphere of hydrogen are reviewed in this paper. Since thereaction between hydride-forming element and hydrogen is reversible, the phasetransformation from metal to hydrides in the course of combustion synthesis is, ingeneral, a multi-step reaction. The effects of combustion parameters such as initialtemperature, hydrogen pressure, and so on, on the physical properties and hydriding/dehydriding kinetics of metal hydrides are also reviewed.