DEVELOPMENT OF TANTALUM PENTOXIDE COATINGS BY CHEMICAL-VAPOR-DEPOSITION

Thermochemical considerations clearly indicate a need for the protection of SiC and Si3N4 materials from HCl- and Na2SO4 induced corrosion. Ta2O5 has been identified as a material which may be suitable for such a protective coating. Thermodynamic calculations have indicated a range of temperatures, pressures, and reactant concentrations under which Ta2O5 coatings may be formed as a single phase by chemical vapor deposition. Ta2O5 coatings exhibiting a range of microstructures were obtained experimentally.