Effect of Bionic Unit Shapes on Solid Particle Erosion Resistance of ZrO2-7wt％Y2O3 Thermal Barrier Coatings Processed by Laser

摘要

Inspired by the coupling phenomena in biological systems,to improve the solid particle erosion resistance of Thermal Barrier Coatings (TBCs),different kinds of bionic units were made on the coating surfaces using Bionic Coupled Laser Remelting (BCLR) process.The NiCoCrAIYTa/ZrO2-7wt％Y203 double-layer structured TBCs were prepared by air plasma spraying.The microstructure,microhardness and phase composition of the as-sprayed and bionic specimens were examined.The solid particle erosion behaviors of bionic specimens as function of bionic unit shape were investigated.The results indicated that the bionic specimens had better erosion resistance than the as-sprayed specimen.The specimen with striation and grid bionic units had the better erosion resistance,while the dot showed the worse.The bionic units were characterized by the dense colunnar crystal structure and the high hardness,which are the main reasons for improving the erosion resistance.Under the synergistic action of the shear stress and normal stress on the protrusive coating surface,the erosion failure of the as-sprayed TBCs was proved to be the fracture and spallation of the splats.By contrast,the spallation of segmented bionic unit occurred in the overlapping area between the adjacent laser irradiation,and the erosive unit surface presented the clear and deep furrows,which revealed that the erosion failure mechanism of bionic TBCs was dominated by brittle and some ductile erosion.These results showed more opportunities for bionic application in improving the solid particle erosion resistance of components in the windy and sandy environment.