Determination and interpretation of the hydriding and dehydriding kinetics in mechanically alloyed LaNiMg17 composite

The hydriding/dehydriding (H/D) rates in the two-phase (α-β) region of LaNiMg17 were determined and investigated at temperature ranges from 523 to 623 K under approximately isobaric condition. The obtained data of H/D rates indicated that the rate-controlling step was the hydrogen diffusion through the hydride phase. The new model developed by us has been used to these experiments, from which two formulae describing the H/D processes are obtained in an explicit analytic form. The corresponding activation energy is 71000 J/mole H2 for both processes. It can be seen that the theoretical calculation consists with the experimental data very well.