摘要
Environmental barrier coatings(EBCs)effectively protect the ceramic matrix composites(CMCs)from harsh engine environments,especially steam and molten salts.However,open pores inevitably formed during the deposition process provide the transport channels for oxidants and corrosives,and lead to premature failure of EBCs.This research work proposed a method of pressure infiltration densification which blocked these open pores in the coatings.These results showed that it was difficult for aluminum to infiltrate spontaneously,but with the increase of external gas pressure and internal vacuum simultaneously,the molten aluminum obviously moved forward,and finally stopped infiltrating at a depth of a specific geometry.Based on the wrinkled zigzag pore model,a mathematical relationship between the critical pressure with the infiltration depth and the pore intrinsic geometry was established.The infiltration results confirmed this relationship,indicating that for a given coating,a dense thick film can be obtained by adjusting the internal and external gas pressures to drive a melt infiltration.
基金
supported by the National Natural Science Foundation of China(No.51901175)
the Guangdong Province Outstanding Youth Foundation(No.2021B1515020038)
the Guangzhou Technical Research Program(No.201906010015)
the Industry University Research Project funded by Aero Engine Corporation of China(No.HFZL2019CXY015)
the Postdoctoral Research Foundation of China(Nos.2020T130499 and 2019M653602)
the National Program for Support of Top-notch Young Professionals.
