Effect of tungsten-containing additives (WB/ WSi2/ W) on ablation behavior of ZrB2-SiC coating

Abstract

ZrB2-SiC based composite coatings with different tungsten-containing additives (WB/WSi2/W) were prepared by vacuum plasma spray. The ablation resistance of the coatings was evaluated by a plasma flame. The phase composition and microstructure evolution of the composite coatings during ablation were characterized and the function of tungsten-containing additives was focused on. The results showed that the introduction of tungsten-containing additives could obviously reduce the surface temperature by about 300 °C during the ablation processes. Based on microstructure observation and thermodynamic calculations, it was considered that the evaporation of WO3 and formation/existence of pure W with high thermal conductivity contributed a lot to the reduction of the surface temperature.