A CrSi₂-SiC-Si multiphase ceramic coating for SiC coated C/C composites against oxidation at 1773 K and 1973 K

To increase the long-term service duration of Carbon/carbon (C/C) composites at high-temperatures (≥1773 K), a CrSi₂-SiC-Si coating (∼110 μm) was constructed on the SiC-coated C/C composites. The coating is a homogeneous mosaic structure consisting of both the CrSi₂ filled into the pores and the Si-rich phase and is well bonded with the SiC inner coating. The composite coating exhibited excellent oxidation resistance at different temperatures with a mass loss of only 1.44 % after oxidation for 530 h in air at 1773 K and 4.36 % after oxidation for 23 h in air at 1973 K. The protective mechanism is attributed to the oxide scale consisting of Cr₂O₃ with high thermal stability and SiO₂ with self-healing capability during the oxidation process.