The role of interfacial curvature in the hysteresis in metal-hydrogen systems

A phenomenological theory based on interfacial thermodynamics is presented to explain the role of interfacial curvature in the hysteresis in metal-hydrogen systems. The influence of coherent matrix-hydride interface curvature on hydride formation and decomposition is outlined. The effect of finite phase boundary curvature on pressure, temperature and solvus hysteresis is derived. The applicability of the model to the hysteresis of Pd-H system is presented. Interfacial curvature effects become insignificant when the interface curvature becomes greater than 1 mu m.