High-Temperatures Oxidation of AlN–TiCrB₂ Composites.
I. Kinetics and Mechanism of Air Oxidation at 1600 °C

Abstract

Thermal gravimetry and differential thermal analysis are employed to study the oxidation resistance of AlN–TiCrB₂ materials in air up to 1600 °C. The kinetic curves for the materials are parabolic, indicating that oxidation leads to the formation of dense oxide layers preventing oxygen diffusion deep into the samples. With increasing TiCrB₂ content of the composite, its oxidation resistance decreases since B₂O₃ appears in and evaporates from the oxide film, resulting in its partial failure. The oxidation rate constants and activation energies depending on material composition and temperature are calculated with the Arrhenius equation based on collisions of oxygen molecules on the samples. The data obtained indicate that the oxidation mechanism is dependent on the material composition and temperature