Microstructural modifications induced by hydrogen absorption in Mg5Ga2 and Mg6Pd

We have recently proposed a new method to design one-dimensional structures of MgH₂ in the nano- and micrometer ranges by hydrogen-induced disproportionation of bulk Mg₂₄Y₅. The present study confirms the same behavior in hydrogenated Mg₅Ga₂ and Mg₆Pd. Single-crystalline one-dimensional structures and microparticles of MgH₂ are formed by hydrogen absorption and subsequent partial disproportionation of Mg₅Ga₂ and Mg₆Pd. The MgH₂ whiskers and particles grow with different morphologies for different alloying partners. Growth mechanisms are proposed in relation to the morphology and the chemical surface composition of original compounds.