Equilibrium vacancy concentration in Pd–H solid solutions

Abstract

A simple framework has been developed for the estimation of the equilibrium concentration of vacancies in metal–hydrogen systems using the quantum results for the vacancy–hydrogen cluster energies. Vacancy formation obeys Fermi–Dirac statistics in assuming different cluster configurations. The presence of hydrogen results in the equilibrium concentrations of vacancies that are many orders of magnitude higher than the thermodynamic vacancy concentration of the pure metal. This is in accordance with the observed changes in the kinetics of the host lattice and suggests possible implications to the mechanical properties.