The Effect of Ta on the Kinetics and Mechanisms of High-Temperature Oxidation of the (hf,ta)b2–sic Ceramics

This study focuses on the kinetics and mechanisms of oxidation at 1200 and 1650°C for the ceramics based on (Hf,Ta)B2-SiC. The effect of primary phase content on structural and morphological features of the nascent oxide layers and the efficiency of their protective action is analyzed. The evolutionary changes in the structure at the micro and nanolevels are studied. Doping the ceramics with Ta is found to negatively or positively affect their oxidation resistance, and substantiation for this effect is provided. Ceramics containing 8% SiC are shown by their maximum high-temperature oxidation resistance at 1200°C and 25% SiC at 1650°C.