Mechanism of hydrogen capacity dependence on the hydrogenation temperature

It is known that decreasing the hydrogenation temperature results in a loss of hydrogen capacity of Mg powders. Based on the model that hydrogen capacity is reached when hydride colonies/crystals formed on the surface of particles impinge on each other and form a continuous layer, it is elucidated, through a two-step hydrogenation experiment and detailed microstructural analysis, that the reduced hydrogen capacity at low temperatures is associated with an increase in the hydride nucleation rate.