Abstract

Carbon/carbon (C/C) composites have shown great scope as thermal structural materials in the aerospace industry. However, the material is restricted from being applied in oxygen-containing airflow with high temperatures and high mechanical stress due to high-temperature oxidation. In this study, the ZrB2-SiC-La2O3 coatings with different La2O3 contents were prepared on the surface of SiC-coated C/C composites by atmospheric plasma spraying technology. Focusing on the phase and morphology evolution, the oxidation behavior of the composite coatings at 1500 degrees C for 10 h was studied, which will guide the future application of ultra-high temperature ceramics coatings on C/C composites. The results showed that the composite coating with 10 wt% La2O3 displayed better oxidation resistance. The morphology of the coating after oxidation showed that La atoms partly substitute Zr atoms to form the high-temperature stable phase (La0.1Zr0.9)O1.95 and Zr(La)-O-C compounds. These phases not only restrained the ZrO2 phase transformation but also formed a dense barrier with the uniformly distributed molten phase to resist oxygen erosion, providing effective high-temperature protection for C/C composites. Nevertheless, the excessive addition of La2O3 destroyed the viscosity of the melt phase, which further reduced the high-temperature stability of the oxide layer.

Keywords Plus：C/C COMPOSITES，TEMPERATURE-RANGE，RESISTANCE，MICROSTRUCTURE，PERFORMANCE，CERAMICS，STRATEGY，ABILITY

Published in APPLIED SURFACE SCIENCE，Volume 685；10.1016/j.apsusc.2024.162047，MAR 15 2025