Evolution of the oxidation behaviors of highly oxidation-resistant (Ti0.8Nb0.2)C in 1000-1200 °C steam

The evolution of the oxidation behaviors of the highly oxidation-resistant (Ti0.8Nb0.2)C was investigated in a 1000-1200 degrees C steam environment. For the specimen oxidized below 1200 degrees C, a compact oxide layer less than 7 mu m thick was obtained. By increasing the temperature to 1200 degrees C, the oxide layer grows quickly to over 30 mu m. Variable distribution of Ti and Nb in the oxide scales reveals the significance of the outward diffusion of the metal elements during oxidation. Synchronized variations in Ti and Nb were observed in the specimen oxidized below 1200 degrees C, while the distribution trends of Ti and Nb were opposite in the specimen oxidized at 1200 degrees C. The incorporation of Nb effectively lowered the diffusion rate of Ti through the oxide scales and the grain growth of the oxides. Suppressed diffusion and dense oxide scales are responsible for the excellent oxidation resistance of (Ti0.8Nb0.2)C below 1200 degrees C.

Automated summary

The oxidation behavior of (Ti0.8Nb0.2)C in a steam environment between 1000-1200 degrees Celsius was investigated. It was found that below 1200 degrees Celsius, the oxide layer was compact and less than 7 micrometers thick, while at 1200 degrees Celsius, the oxide layer grew quickly to over 30 micrometers.