Comparison of the Oxidation Behaviour of Three Dense Hiped Materials: Titanium Nitride, Aluminium Nitride Materials and a 50-50 mol.percent AlN-TiN Composite

摘要

Dense titanium nitride and aluminium nitride materials as well as a 50-50 mol.percent AlN-TiN composite were obtained by hot isostatic pressing of encapsulated powders. The oxidation studies were carried out in a flow of pure oxygen at high temperature (900-1400deg C) and atmospheric pressure. By comparison to other transition metal nitrides (TaN, HfN, ZrN), where a limiting reaction process is located at the nitride/oxide interface and a maltese cross shape of the final sample is observed, we have noticed, for all the three non-oxide ceramics (TiN, AlN, and the AlN-TiN composite), a diffusional regulating process and conservation of the specimen's cubic shape. The diffusion regime may be explained by the high compacity of the external oxide layers which act as diffusion barriers.