A study of high-speed slurry erosion of NiCrBSi thermal-sprayed coating

The test specimens of NiCrBSi coating were prepared using the high velocity oxy-fuel spraying technique with a post-thermal treatment. Their high-speed slurry erosion characteristics have been systematically studied. SUS304 stainless steel was selected as the comparison material. Experimental results show that the NiCrBSi sprayed coating exhibits a much better slurry erosion resistance than the SUS304 stainless steel. The erosion rate for the NiCrBSi sprayed coating slightly increases with the impinged angle. However, a maximum erosion rate appears at an impinged angle of around 30° for SUS304 stainless steel. Both NiCrBSi sprayed coating and SUS304 stainless steel exhibit impinged surfaces with lots of furrows at an impinged angle of 30°. At a high impinged angle of 90°, the SUS304 stainless steel exhibits an impinged surface with lots of overlapping and irregular concavities, while, these features are less obvious for NiCrBSi sprayed coating. The hardness of SUS304 stainless steel increases significantly with increasing impinged angle during the high-speed slurry erosion. But, there is no obvious work hardening for the NiCrBSi sprayed coating due to its extra-high hardness and less plastic deformation, even at a high impinged angle of 90°.