SiC_f/SiC表面环境障涂层的基体无损去除方法

Environmental barrier coatings (EBC) can be applied to the surface protection of silicon carbide ceramic matrix composites (SiC_f/SiC-CMC) from combined corrosion of water-oxygen. Local spallation or delamination would occur after exposure to high-speed and high temperature flame ablation. In order to recycle and reuse the extremely expensive CMC materials, it is urgent to develop EBC remanufacturing technology. Removing the original failed EBC is the most important and primary step for the deposition of new EBC. In this study, a substrate-lossless removal method for the failed EBC is proposed, based on the structural and mechanical property analysis of the multi-layered EBC and substrate. Conventional methods, such as chemical corrosion, high pressure water impact, laser cleaning, are difficult to be directly applied to the removal of EBC coating due to the inevitable substrate damage. By comparing and analyzing the mechanical properties of multi-layered EBC and substrate, a selective erosive method with sandblasting was proposed. By using a self-developed EBC removal device, the effects of parameters on coating removal efficiency were investigated based on the surface morphology after removal. In addition, the non-destructive characteristics of substrate and the removal mechanism of coating were discussed. The substrate-lossless removal method of failed EBC provides fundamental support for the development of overall EBC remanufacturing technology.