陶瓷基复合材料可磨耗环境障涂层制备及性能OA北大核心CSTPCD

With the application of shrouds made of silicon carbide ceramic matrix composite(SiC-CMCs),the abradable coating technology suitable for SiC-CMCs is urgently needed.The four-layer structure of BSAS(Ba0.75Sr0.25Al2Si2O8)-polyester-based abradable environmental barrier coating(A/EBCs)was prepared by atmospheric plasma spraying.The influence of process parameters on the porosity and the structural evolution of the layer at 1300℃ were investigated.The phase structure,microstructure and coating composition were characterized by XRD,SEM,EDS and TEM respectively.The results show that the porosity of BSAS-polyester abradable top layer is 26.4％-36.8％.And the temperature-sensitive parameters of BSAS-polyester particles are primary gas(argon)flow,second gas(hydrogen)flow and spraying distance.In contrast,the speed-sensitive parameters are primary gas(argon)flow.The primary gas(argon)flow has the opposite effect on the particle temperature and velocity of the BSAS-polyester.The abradable surface layer is oxidized at 1300℃for 300 h and maintains monoclinic phase structure,stable stucture and composition,and locally precipitates spherical amorphous silicon oxide particles.Furthermore,the coating abradability was evaluated by high-temperature and high-speed scraping test.Nano-scale Ni-based superalloy particles adhesion on the surface of the coating are found,and the blade incursion depth ratio(IDR)is 20％,which meets the requirements of the abradable sealing coating.