Oxidation behavior of titanium boride at elevated temperatures

Abstract

Oxidation behavior of titanium boride (TiB2) powder was investigated by thermal analyses (DTA and TG) and X-ray diffraction. From the DTA and TG analyses, a broad exothermic peak with a continuous weight gain was observed between 450 and 750°C. The exothermic peak was bimodal with a minimum around 550°C. High-temperature X-ray diffraction spectra taken around this temperature were featureless. These observations suggest that a high viscosity liquid-phase of B2O3 forms as a thick surface coating which then prevents further oxidation of the underlying material. The X-ray diffraction analyses revealed that the reaction products were TiO2 (anatase) at lower temperatures and TiO2 (rutile) at higher temperatures. TiBO3 was also identified in the material after heating to 1000°C.