Oxidation behaviour of a continuous carbon fibre reinforced ZrB2-SiC composite

The oxidation behaviour in air of a hot-pressed ZrB2-SiC-Cf composite was investigated. Tests from 25 to 1550 degrees C in air were carried out at a rate of 10 degrees C/min and 45 degrees C/min. Then, 6 h isothermal runs were conducted in air at 800, 1000, 1200, 1400 degrees C, after heating the samples in argon at 30 degrees C/min. Below 1000 degrees C the kinetics was dominated by an exponential weight loss due to fibre consumption. Above 1000 degrees C, weight loss started to be significantly counterbalanced by weight gain due to the formation of a layer of SiO2 and B2O3. Kinetic parameters were evaluated.