Decomposition behavior of MGH2 prepared by reaction ball-milling

Mg can be directly hydrided into MgH2 and γ-MgH2 under the action of catalyst ZrFe1.4Cr0.6 by reaction ball milling. The increase of hydrogen content, depending on the grinding time, does not affect the thermodynamic property of the formed hydride. The hydrided phases posses markedly improved desorption kinetics, even at 513 K the decomposition could proceed at moderate rate. According to the analyzing result of local Avrami exponent, it was found that the nucleation was only rate-dominant in the initial decomposition, and then the main reaction mechanism was growth controlled by the diffusion of hydrogen atom. ZrFe1.4Cr0.6 distributing uniformly on the surface and in the bulk matrix, played an important role in accelerating the diffusion of hydrogen atom.