A method for assessing the volatility of oxides in high-temperature high-velocity water vapor

A steam-jet furnace was utilized to assess the volatility of SiO2, TiO2 and Y2O3 in a simulated turbine engine environment. Specimens were exposed in the steam-jet furnace at 1 atm H2O, steam temperatures of 1240–1300 °C, and gas velocities of 165–177 m/s. The jet of steam impinged on the specimen under study leading to surface recession via the formation of volatile hydroxide species. Linear volatilization kinetics were observed for SiO2. The measured recession rate of SiO2 was in reasonable agreement with the calculated recession rate based on assessed thermodynamic data for Si(OH)4 (g). The measured recession rate of TiO2 in this study was considerably higher than the recession rate based on measured thermodynamic data for TiO(OH)2 (g) and lower than prior experimental results. The measured recession rate of Y2O3 was in fair agreement with the calculated recession rate using estimated thermodynamic data for Y(OH)3 (g) formation and was significantly lower than prior experimental results.