Comparative Tribological Behavior of V(N,C) and VC Diffusion Coatings
Hard coatings show various tribological behaviors against different contact materials (counter-faces) during dry sliding depended on their microstructure, surface morphology and encountered tribological systems and condition. In this work, the tribological and wear mechanisms of vanadium carbide (VC) and vanadium nitrocarbide (V(N,C)) layers were examined against WC/Co cemented tungsten carbide pin during pin-on-disk sliding wear testing. The V(N,C) layer was produced by a duplex surface treatment involving the gas pre-nitrocarburising followed by thermo-reactive diffusion (TRD) vanadizing technique. The coating layers were characterized by a cross sectional and morphological examination methods and X-ray diffraction analysis to identify damages of the coating’s surface. Wear mechanisms were determined by SEM microscope in BSI and SE mode accompanied by EDS analysis. Results revealed that the surface morphology of the V(N,C) coating consist of dense and smooth layer in comparison with the VC coating surface which reveals a non-uniform structure with chasms. It was determined that the activation of tribo-chemical system and oxidizing of the coating layer together with minor plastic deformation are the dominant wear mechanism in the V(N,C) coated steel. In the case of the VC coating, combination of abrasive wear and adhesion of pin material to coating and vice versa are the major impairing mechanisms.
Andreas Öchsner, Graeme E. Murch, Ali Shokuhfar and João M.P.Q. Delgado
F. Fazlalipour et al., "Comparative Tribological Behavior of V(N,C) and VC Diffusion Coatings", Defect and Diffusion Forum, Vols. 297-301, pp. 1183-1189, 2010