Influence of thickness and surface roughness on impact wear and impact lifetime of HVOF-sprayed coatings

Abstract

A number of industrial applications today require thermally sprayed coatings that exhibit good adhesion, high temperature and chemical resistance, and can withstand particle impacts or dynamic interactions with components. A common example of a high-velocity oxygen fuel (HVOF) sprayed coating with such the aforementioned properties is Cr3C2–25%NiCr. The objective of this study is to examine the impact of varying thicknesses and surface roughness on the impact lifetime and impact wear of Cr3C2–25%NiCr coatings. A series of Cr3C2–25%NiCr coatings were subject to analysis using a dynamic impact tester with impact loads of 200 N, 400 N, and 600 N. The results indicated that there exists an optimal coating thickness with the highest impact lifetime. The results were discussed using microstructural analysis of the impact coatings and finite element simulation. The maximum impact lifetime was achieved with the optimal combination of sample material properties, substrate mechanical properties, coating thickness, and residual stress. Furthermore, it was demonstrated that surface does not influence the impact lifetime of the coating, but does affect the accuracy of its determination.