Silicon carbide whisker-reinforced alumina coatings on SiC-SiC composites

MER has developed a new, highly creep resistant SiC fiber. Incorporation of these fibers into an SiC matrix resulted in a new class of SiC-SiC composites ideally suited for heat exchanger and other energy-related applications. However, high temperature use of SIC ceramics in corrosive environments is limited to about 1200 degrees C. Efforts to apply protective alumina coatings on SiC-SiC composites have failed in the past primarily due to the thermal mismatch between the SiC substrate and alumina A new SiC whisker-reinforced CVD alumina coating technology was developed by MER. This new type of alumina coatings on MER SiC-SiC composites survived thermal shock testing at 1500 degrees C. Microstructural and thermomechanical properties of this new CVD coating are reported.