Tribological behaviour of HVOF sprayed WC-12Co, WC-10Co-4Cr and Cr3C2-25NiCr coatings

In the present work erosive and abrasive wear behaviour of HVOF deposited WC-12Co, WC-10Co-4Cr and Cr3C2-25NiCr coatings was investigated. The maximum wear rate was exhibited by Cr3C2-25NiCr coating under both solid particle erosion and abrasion. The coatings exhibited composite erosion response. The erosion response was rationalized on the basis of velocity exponents, erosion mechanisms and mechanical properties. Erosion damage parameter and severity of contact can be useful indicator of transition in failure modes. The wear mechanisms were influenced by microstructure of the coatings and the test conditions, involving fracture and pull out of carbides, removal of splats and subsurface cracking. The lowest coefficient of friction exhibited by Cr3C2-25NiCr coating was attributed to formation of tribo oxide film.