HfB2-doped ZrB2-30 vol.% SiC composites: Oxidation resistance behavior

Abstract

To investigate the HfB2 on microstructure and oxidation resistance of ZrB2-30 vol% SiC, ZrB2-30 vol% SiC composites with different amounts of HfB2 (4, 8, and 12 vol%) were consolidated by Spark Plasma Sintering method (SPS). Microstructural evaluations were done by scanning electron microscopic (SEM). To investigate the oxidation resistance, the samples were placed in a box furnace at the temperature of 1400 C for different times. The samples were weighed before and after the oxidation and the Δw was applied as a criterion of oxidation. The thickness of SiO2 layer and Si depleted layer were also used as oxidation criterion. The results showed that HfB2 addition caused to decrease Δw and better oxidation resistance.