Oxidation and ablation protection of plasma sprayed LaB6-MoSi2-ZrB2 coating for carbon/carbon composites

To improve the high-temperature stability of carbon/carbon (C/C) composites, a LaB6-MoSi2-ZrB2 (LMZ) coating was deposited on SiC-encapsulated C/C composites by supersonic atmospheric plasma spraying. The sprayed LMZ coating showed a significant improvement of oxidation and ablation protective abilities relative to MoSi2 and ZrB2 coatings, which could protect C/C composites for more than 80 h at 1773 K in static air and 60 s above 2000 K under oxyacetylene flame. La and Zr acted as the role in accelerating the liquid phase sintering of SiO2-based oxides, forming a compact Si-Zr-La-O compound scale to enhance the high-temperature stability of LMZ coating.