General regularities of thermal decomposition of transition metal dihydrides in a medium with low hydrogen partial pressure

Abstract The results of the calorimetric studies of thermal dissociation of titanium, zirconium, magnesium, and palladium hydrides performed in recent years are presented. The multiplet character of thermal dissociation characteristic of all these hydrides is shown. A good correlation between the course of differential scanning calorimetry curves and the results of thermogravimetry has been demonstrated. The discrete nature of the decomposition processes is established. A sequence of mechanisms occurring during the heating of transition metal dihydrides in a medium with a low partial pressure of hydrogen has been proposed: rearrangement in the hydride phase; destruction of metal - hydrogen bonds to form a solid solution supersaturated with hydrogen; diffusion of hydrogen to the interface of solid phase - environment; molization of hydrogen at the exit from the solid phase.