MgH2 -> Mg phase transformation driven by a high-energy beam: An in situ transmission electron microscopy study

The dynamics of a phase change have been studied using the electron beam in a transmission electron microscope to transform MgH2 into Mg. The study involved selected-area diffraction and electron-energy-loss spectroscopy (EELS). The orientation relation ([001](MgH2)//[(2) over bar 110](Mg) ((1) over bar 10)(MgH2)//(0001)(Mg)), obtained from the electron diffraction study, has been used to propose a model for the movements of magnesium atoms during the phase change. The in situ EELS results have been compared with the existing H-desorption model. The study aims to describe the sorption dynamics of hydrogen in MgH2, which is a base material for a number of promising hydrogen storage systems.