Preparation and oxidation behaviour of SiC-based ceramics with TaB2 addition

Abstract

Liquid-phase-sintered SiC ceramics (LPS-SiC) with the sintering additives of Y2O3–Al2O3 and Y2O3–Al2O3–TaB2 were prepared. The oxidation behaviours of these sintered SiC ceramics were studied after oxidation test at 1300 °C in air. In comparison with SiC ceramicwith Y2O3–Al2O3, the addition of TaB2 inhibited the formation of the secondary phase of Y3Al5O12 (YAG) and homogeneous distribution of Al element in the SiC matrix was evidenced. After oxidation at 1300 °C, SiC ceramic without TaB2 additive was found to possess a two-layer structure within the oxidation region. In contrast, SiC ceramic with TaB2 additive demonstrated the three-layer structure consisting of a dense intermediate layer of SiO2, which could protect the SiC matrix from further oxidation.