ABSTRACT

Abstract. The oxidation behaviour of nanoscale multilayer PVD TiAINNN coatings heat-treated in air 600°C for 30minutes were studied using TEM. A duplex surface oxide was found, consisting in a number of phases, with an outer layer rich in V z05, AIV0 4 and an inner layer containing VzOs and V0 2 and possibly AlzTi0 5 with Ti02 extending across both layers. Oxidation occurred preferentially along columnar grain boundaries, but the oxidation front did not follow the multilayer structure. The oxidation mechanisms are discussed.