Hfb2-Doped Zrb2-30 Vol.% Sic Composites: Oxidation Resistance Behavior

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 Delta w 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 Delta w and better oxidation resistance.