|About this Abstract
||Materials Science & Technology 2020
||High Temperature Corrosion and Degradation of Structural Materials
||Thermochemical Stability of EBC Silicates in High-temperature High-velocity Water Vapor
||Mackenzie Ridley, Elizabeth J. Opila
|On-Site Speaker (Planned)
||Elizabeth J. Opila
Complex silicates such as hafnium silicates, barium strontium alumino silicates, and rare earth-monosilicates and -disilicates are candidates for environmental barrier coating systems. One key property requirement of these materials is their thermochemical stability in water vapor-containing combustion environments. All these complex silicates react with high temperature water vapor to form Si(OH)4(g) and solid silica-depleted product phases. The rate of this reaction depends on the temperature, water vapor partial pressure, gas velocity and the silica activity in the silicate. However, other factors such as the stability of the other oxide components and the resulting product microstructure also play a role in determining the material degradation rate. Results from “steam-jet” furnace exposures of complex silicates in high-temperature (1200 to 1400C) high-velocity (up to 200 m/s) water vapor will be presented, exploring the rate limiting mechanisms for thermochemical degradation of these EBC candidate materials.