OXIDATION RESISTANCE MECHANISM OF ZrB2–Al2O3–Y2O3 COMPOSITE PARTICLES

Although ZrB2 has some excellent performances, it is easily oxidized in the high-temperature air, which is deadly shortcoming as high-temperature materials. To increase the high-temperature performances of ZrB2, Al2O3 and Y2O3 particles are coated on the ZrB2 surface to prepare ZrB2–Al2O3–Y2O3 composite particles. The oxidation resistance mechanism of ZrB2–Al2O3–Y2O3 composite particles is investigated by DTA-TG, TEM, and XRD. The surface of ZrB2 particle is coated with compact Al2O3 and Y2O3 particles, which establishes the foundation to attain good oxidation resistance. ZrB2 particle is mainly oxidized to increase the weight, from 600°C to 800°C. B2O3, obtained through the oxidization reaction, might coat on the surface of ZrB2 particle to retard the oxidization reaction, which further increases the oxidation resistance. The oxidation resistance of coated ZrB2 particle is far better than that of original ZrB2 particle.