Oxidation resistance of zirconium diboride powder.

Abstract

The oxidation resistance of zirconium diboride (ZrB2) powder at high temperatures was investigated in order to determine the possibility of the use of additional material for improvement of the oxidation resistance in carbon-carbon (C/C) composites. ZrB2 powder with an average particle size of about 10μm was used in this experiment. The samples were oxidized at 300 to 1000°C for 5min to 25h in air. The weight changes were measured to estimate the oxidation resistance. The oxidation of samples oxidized for short oxidation time of 5min started at 700 to 800°C, and the weight gain increases with increasing oxidation temperature. On the other hand, at the oxidation time of above 0.5h, a maximum weight gain value at 700°C was observed. After that the weight gain decreased monotonically with increasing oxidation temperature. Based on the results of the X-ray diffraction analysis, monoclinic ZrO2 was present on the surface of the samples oxidized at 700°C and above. The peaks of tetragonal ZrO2, cubic ZrO2 and B2O3 could not be identified. The B2O3 of oxidation product vitreousd or vaporized at high temperature.