High-temperature water-vapor reaction mechanism of barium strontium aluminosilicate (BSAS)

Environmental barrier coatings (EBCs) are used in commercial turbine engine applications as protection for ceramic matrix composites, yet the high-temperature water vapor reaction mechanism EBC materials is not fully understood. Here, barium strontium alumino-silicate (BSAS), an early generation candidate, was determined from time and temperature dependences of material loss. BSAS exposures were performed at 1200 °C, 1300 1400 °C 24, 48, 72 h, maximum gas velocities ~ 240 m/s. FactSage thermodynamic calculations shown to support experimental findings, where steam consisted volatilization all oxide constituents gaseous metal hydroxide species, i.e. Ba(OH) 2 , Sr(OH) Al(OH) 3 Si(OH) 4 (g).