OXIDATION RESISTANCE MECHANISM OFZrB₂–Al₂O₃–Y₂O₃COMPOSITE PARTICLES

Abstract

Although ZrB 2 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 ZrB 2 , Al 2 O 3 and Y 2 O 3 particles are coated on the ZrB 2 surface to prepare ZrB 2 – Al 2 O 3 – Y 2 O 3 composite particles. The oxidation resistance mechanism of ZrB 2 – Al 2 O 3 – Y 2 O 3 composite particles is investigated by DTA-TG, TEM, and XRD. The surface of ZrB 2 particle is coated with compact Al 2 O 3 and Y 2 O 3 particles, which establishes the foundation to attain good oxidation resistance. ZrB 2 particle is mainly oxidized to increase the weight, from 600°C to 800°C. B 2 O 3 , obtained through the oxidization reaction, might coat on the surface of ZrB 2 particle to retard the oxidization reaction, which further increases the oxidation resistance. The oxidation resistance of coated ZrB 2 particle is far better than that of original ZrB 2 particle.