Microstructure, properties and formation mechanism of SiO2/SiC nano-coating onto carbon fiber by non-electrode plasma electrolysis

Recently we have developed a novel non-electrode plasma electrolysis technique in order to rapidly prepare SiO₂/SiC nano-coating onto carbon fiber. The surface and cross-sectional microstructures of the SiO₂/SiC nano-coating were systematically investigated. The nano-coating was dense and roughly uniform, mainly composed of amorphous SiO₂, where a small amount of SiC was distributed. A superior bonding was observed between the nano-coating and the fiber substrate. The cross-sectional TEM revealed ∼80 nm in the thickness for the coating. The SiO₂/SiC nano-coating significantly reduced the oxidation rate with the burn-out temperature increasing from 880 °C to 1250 °C. It was proposed that the heat evolution, mechanical effect and plasma chemical reactions had a critical effect on the formation of the nano-coating. We believe that the novel non-electrode plasma electrolysis technique will find a wide range of applications in modifying the interface of carbon fiber reinforced composite materials.