Influence of epoxy resin on the microstructure and cavitation erosion of as-sprayed 8YSZ coating

Abstract

Abstract The microstructures of materials are sensitive to shock waves and microjets induced by bubble collapse. The microstructure of coatings is thus closely related to their cavitation performance. Coating defects always act as the preferential sites for the bubble growth; thus, the materials around pores have been spalled preferentially under strong impact. In this study, epoxy resin (ER) was introduced into as-sprayed 8\u202fwt% yttria-stabilized zirconia (8YSZ) coating by vacuum impregnation to prepare 8YSZ-ER coating. Results showed that the hardness, toughness, cohesive strength, and density of 8YSZ-ER coating are greatly improved. Cavitation performance is also improved; 8YSZ coating exhibited only a deceleration period whereas 8YSZ-ER coating showed a long steady-state period. This finding was mainly attributed to the enhanced compactness and cohesive strength of 8YSZ-ER coating, which caused the impact force to be evenly distributed on the specimen surface without accumulating in the pores. Cracks were also deflected, turned and terminated due to the presence of ER. Moreover, the relationship between ER aging and the damage mechanism of 8YSZ-ER coating under cavitation erosion was also examined.