Anti-ablation properties of MoSi₂-W multi-layer coating system deposited by atmospheric plasma spray

Carbon fibre reinforced carbon (C/C) composites have become an important material for hyper thermal conditions and have been widely used in aerospace and aviation industry. However, the composites will be ablated above 723 K in an oxygen-containing atmosphere. The MoSi₂-W multi-layer anti-ablation coating system was deposited by atmospheric plasma spray. The supersonic flame caused by kerosene and oxygen was selected to examine the property of the coatings. Samples of three groups were ablated by the flame at 1600°C. The speed of gas flow was 850 m s^-1. The MoSi₂-W multi-layer anti-ablation coating system can protect the graphite matrix effectively. The products of ablation include SiO₂, Mo₅Si₃ and MoO₃. With the prolongation of time, the aggregates sinter and grow up. The network structure of the coatings is caused by the evaporation of MoO₃ and loss of SiO₂.