Tribological study of Ni-Cr-5Al2O3 thermal spray coating: A comparison of post processing techniques

Abstract

Abstract Engineering materials are known to show degradation in terms of tribo-corrosion characteristics in marine environment. The concurrent increase in erosion and corrosion resistance can make them more appealing for structural applications. The thermal spray coatings are typically used to mitigate the degradation of structural components. Although, the microstructure of as-sprayed coating indicates inconsistency in the form of distinct splats and elemental segregation. Furnace annealing, microwave processing and stationary friction processing (SFP) are performed to improve the non-homogeneous microstructure of the thermal spray coating. SFP has several attractive properties to refine the grain structure and reducing the defects density on the surface. Therefore, SFP has been explored as a surface modification technique for thermal spray coating with an aim to enhance the performance of the processed coating. Slurry erosion and erosion corrosion tests are conducted on as-sprayed and processed coatings at normal and oblique impingement angle. Erosion rate of SFPed sample is comparatively lower than that of the as-sprayed, furnace annealed and microwave processed samples in both slurry erosion and erosion corrosion. Furthermore, the SFPed coating indicated least corrosion rate as compare to furnace annealed, microwave coating and as-sprayed coating.