Oxidation behavior of ZrC-based composites in static laboratory air up to 1300 °C

Abstract

Two ZrC-based composites, viz., ZrC+20vol.%SiC and ZrC+20vol.%SiC+20vol.%ZrB2, were prepared by hot pressing. The oxidation behavior of the composites was studied in the temperature range of 800°C–1300°C in air. From the mass gain tests, the surface and cross-sectional SEM observation and EDS analysis of the oxidized samples, it was found that the ZrC+20vol.%SiC composite seemed to have a high oxidation resistance below 1000°C, but the ZrC+20vol.%SiC+20vol.%ZrB2 composite appeared a more excellent oxidation resistance up to 1200°C. It is main reason that the oxidation rate of ZrC is higher than that of SiC below 1300°C, meaning that SiO2 from SiC is insufficient to form a dense tight protection film; however, the addition of ZrB2 particles promotes the formation of more borosilicate above 1000°C, which exerts more protective effect by self-healing mechanism.