Effect of Y2O3 on the oxidation resistant of ZrSiO4/SiC coating prepared by supersonic plasma spraying technique for carbon/carbon composites

An Y2O3 modified SiC/ZrSiO4 multilayer coating for carbon/carbon (C/C) composites against oxidation at high temperature was prepared by supersonic plasma spraying technique and pack cementation. The microstructure and phase compositions of the coatings were characterized by SEM, EDS and XRD. Oxidation test results show that the coating could protect C/C composites from oxidation at 1823 K in air for 210 h and withstand 25 thermal cycles between room temperature and 1823 K. The excellent protective ability is attributed to the fact that Y2O3 in coating can restrain the phase transformation of the ZrO2 and improve the stability of the SiO2 glass by formation of Y2Si2O7 phase during oxidation.