MoSi₂-based oxidation protective coatings for SiC-coated carbon/carbon composites prepared by supersonic plasma spraying

To protect carbon/carbon (C/C) composites against oxidation, MoSi₂-based oxidation protective coatings for SiC-coated carbon/carbon composites were prepared on them by supersonic plasma spraying. The MoSi₂-based coatings primarily consist of MoSi₂, Mo₅Si₃ and glassy SiO₂. Only a few pinholes and some microcracks are observed on the surface and no through-thickness cracks penetrate the cross-section. Weight loss of the MoSi₂-based coated specimens is only 1.14% after 400h oxidation in air at 1773K and the coated C/C composites remain intact after 11 thermal cycles between 1773K and room temperature. The outstanding anti-oxidation ability is mainly attributable to the formation of SiO₂-based layer on the surface of MoSi₂-based coatings.