High Temperature Oxidation Behaviour of Nanostructured Alumina–Titania APS Coatings

Isothermal oxidation tests at 400, 500 and 600 °C were performed on nanostructured and conventional alumina–titania coatings at different exposure times in air environment. Although parabolic kinetics were observed for most of the experimental conditions, a transition between parabolic and quasi-linear kinetics was found for the conventional system at very demanding conditions (high temperature and exposure time). The better crack propagation resistance of the nanocoating, due to its particular hierarchical microstructure, is thought to be responsible for the enhanced behaviour and the better oxidation resistance observed in this coating.