Oxygen Tracer Diffusion in Polycrystalline Calcium‐Doped Lanthanum Chromites

Abstract

Oxygen tracer diffusion in polycrystalline (La,Ca)CrO3−delta was studied by the gas‐solid isotope exchange reaction in combination with a depth‐profiling technique using secondary‐ion mass spectroscopy, which allowed determination of coefficients of lattice and grain‐boundary diffusion separately. A significant contribution of fast grain‐boundary diffusion was confirmed. The lattice diffusion coefficient increased with increased acceptor content and decreased oxygen partial pressure, which was consistent with the currently established point defect model and, thereby, suggested that the lattice oxide ions diffused by a vacancy mechanism.