Silicon-carbide/boron-containing coatings for the oxidation protection of graphite

Abstract

Silicon carbide with its excellent oxidation resistance and chemical compatibility with carbon is an attractive coating material for the high-temperature oxidation protection of graphite and carbon-carbon composites. One of the major challenges in the development of protective SiC coatings is preventing oxidation of the graphite substrate due to crack formation in the SiC coating. A boron-containing inner layer can prevent significant oxidation through cracks in a SiC outer layer in 1 atm oxygen for up to nine days at 1500 °C. The consistency of the oxidation protection is sensitive to the quality and uniformity of the coatings.