Oxide ion diffusion in optimised LAMOX materials

Abstract

A series of optimised materials in the family with parent compound La₂Mo₂O₉ have been studied using the isotope exchange depth profile technique and SIMS analysis. The data collected indicate that the oxide ion diffusion coefficients in both the parent compound and optimised materials are significantly higher than those reported for any of the fluorite structured electrolyte materials, with a peak value for the La_1.7Gd_0.3Mo₂O₉ composition of 1.41 × 10⁻⁶ cm² s⁻¹ at 800 °C. Further, it was found that the substitution of isotopic oxygen into the ceramic was limited in dry atmospheres but significantly enhanced in a H₂¹⁸O/¹⁶O atmosphere, in common with recent reports on the diffusion/exchange behaviour of the BIMEVOX class of oxide ion conductors.