Oxidation and Volatilization of Silica-Formers in Water Vapor

摘要: At high temperatures, SiC and Si3N4 react with water vapor to form a SiO2 scale. scales also volatile Si(OH)4 species. These simultaneous reactions, one forming the other removing SiO2, are described by paralinear kinetics. A steady state, in which these reactions occur at same rate, is eventually achieved. After state achieved, oxide found on surface constant thickness, recession of underlying material occurs linear rate. The steady-state time achieve rate can be terms constants for oxidation volatilization reactions. In addition, determined from parameters that describe water-vapor-containing environment. Accordingly, maps have been developed show conditions as function reaction constants, pressure, gas velocity. used predict behavior formers environments, such combustion environments. Finally, explore limits model Si3N4.