Studies of chemical diffusion in La1-XSrXCoO3-δ

Abstract Chemical diffusion in La1-x Sr x CoO3-δ with x = 0.3 and 0.6 has been studied by transient thermogravimetry in the temperature range 620--1100°C and at oxygen partial pressures from 1 to 1.6 × 10−4 arm. In view of the defect structure of La1-x Sr x CoO3-δthe chemical diffusion is concluded to reflect diffusional transport of oxygen vacancies. The transient kinetics indicate that the chemical diffusion comprises one diffusion process at near-atmospheric oxygen pressures and two diffusion processes at reduced oxygen pressures. This behaviour may reflect that microdomains of ordered structures are formed as the oxygen vacancy concentration increases with decreasing oxygen activity/oxygen deficiency.