Cavitation erosion of plasma sprayed YSZ coatings produced by feedstocks with different initial sizes

Cavitation erosion of plasma sprayed yttria stabilized zirconia coatings produced by feedstocks with different initial sizes was investigated according to the main guidance of ASTM-G32. Prior to thermal spray, substrates were preheated to 150 and 300 degrees C. The size distribution of pores on the surface of coatings (as-sprayed and eroded) was estimated specifically to investigate its influences on the surface degradation during cavitation erosion. The results indicate that high feedstock size leads to high porosity of coating and low microhardness along with low resistance against cavitation erosion. Additionally, preheating processes could improve the coating resistance against cavitation erosion. The pore size distribution analysis results reveal that initial pores grow up and coalesce and cavitation pits format during cavitation erosion tests.