Identification of Complex Oxidation/Corrosion Behaviours of Boron Nitride Under High Temperature

To characterize the oxidation/corrosion behaviour of boron nitride (BN) at high temperature and to determine kinetics, thermo-gravimetric analyses were performed on BN flat coatings under dry (80% N-2, 20% O-2) and wet conditions (10% H2O, 70% N-2, 20% O-2), at temperatures ranging from 700 to 900 A degrees C. The surface morphology was analysed by scanning electron microscopy. The aim of the study was to understand the complex behaviour of BN at high temperature under wet air. A model was then proposed to explain the recorded mass variations, by taking into account a competition between absorption and volatilization phenomena. Finally, an estimation of the amount of adsorbed species was extracted from these data.