Oxidation-Protective Coatings for Carbon-Carbon Composites

Carbon-carbon composites have attractive properties for high-temperature applications but unfortunately, oxidized at a temperature over 500 °C in the air. Various methods used for protection of C-C composites oxidation such as surface treatment, adding inhibitors in the matrix, and outer coating. High-temperature outer coatings are the most effective method to the protection of C-C composites oxidation. Protective coatings should have low oxygen permeability, compatibility with C-C composites, and adherent to the substrate. SiC is a suitable coating but limited in temperature over 1700 °C and below 1100 °C due to evaporation of silica layer and high viscosity of silica layer respectively and so, multilayer coating system used to solve these problems. SiC coating usually is as a bond layer in coating systems.