Tribological properties of electrodeposited Ni–Co–PTFE composite coatings

Abstract

Nickel and cobalt matrix coatings and their composite coatings with polytetrafluoroethylene (PTFE) particle have been prepared on mild steel substrates by electrocodeposition technique. Microstructural studies, microhardness, friction and wear tests under various loads and sliding speeds have been carried out on these coatings. Scanning electron microscopy (SEM) studies on the worn surfaces were conducted. All the composite coatings exhibited a lower coefficient of friction and better wear resistance when compared with nickel and nickel–cobalt coatings at all loads and sliding velocities studied. However, nickel–cobalt–PTFE composite coatings possessed the lowest coefficient of friction and wear rates. Significant effect of load and sliding velocities on both the coefficient of friction and wear rates of these coatings has been observed. Scanning electron microscopy studies of the worn surfaces reveal delamination process at higher loads.