Experimental Investigation on the Erosion Resistance Characteristics of Compressor Impeller Coatings to Water Droplet Impact

Erosion caused by water droplet impact in high peripheral velocity rotating machinery is an area that is widely researched today. Newer and newer blade protection solutions are being developed for wind power plants, gas turbines, and jet engines to reduce erosion and maintain efficient power generation. However, this phenomenon on turbochargers used in the automotive industry has been the subject of a limited number of studies, despite advanced technologies such as alternative fuels and exhaust gas recirculation increasing the water droplet formation and thus increasing the erosion rate of the impeller. This study investigated the resistance to erosion of three different compressor wheel coatings. Tests were carried out according to the ASTM-G73-10 standard using a custom-developed test apparatus. The degree of erosion was measured by continuous precision mass measurement. Electron microscopy was used to detect structural changes on the surface, both on the base material and on the coating. Significant differences in the extent of erosion were observed for the different coatings. As a result, the isentropic efficiency of the compressor decreased in all cases but varied depending on the type of coating.