Oxidation properties of TiB2/Ti composites

TiB2/Ti composites were fabricated by powder metallurgy. The isothermal oxidation behavior of TiB2/Ti composites sintered at different temperatures (800, 900, 1000 and 1100°C) at 600, 700, 800 and 900°C in air were investigated. The reaction products in the oxidation layer were examined by XRD. The surface morphology and cross-sectional microstructure of the oxidation layer were analyzed by SEM. The results show that an oxidation layer mainly consists of rutile-TiO2, Fe2O3, Al2O3 and B2O3. No other Ti oxides are observed within the oxidation layer. Oxidation kinetics curves of TiB2/Ti composites at 800°C in air show that the oxidation speed is rapid at the beginning of oxidation, but with the increase of oxidation time the oxidation speed becomes slow due to the formation of an oxidation film. With the increase of volume fraction of TiB2 reinforcements and sintering temperature, the oxidation resistance of TiB2/Ti composites can be increased. It is attributed to the formation of the thin and dense oxidation film.