Investigation of Wear Resistance and Corrosion of Ni-PTFE Composite Coatings Prepared by Electrodeposition Method

The results of various research activities have shown that coating is one of the effective ways to increase the corrosion resistance and wear resistance of metallic substrates. Additionally, composite coatings using nanoparticles can also provide further protection to the substrate. In this study, Ni-PTFE coatings were prepared using the electrodeposition process with polytetrafluoroethylene (PTFE) particles at concentrations of 10, 20, or 30 g/L. Their corrosion and wear properties were investigated and compared to those of Ni-P coatings. Using scanning electron microscopy and energy dispersive spectroscopy, the surface morphology and elemental composition of the coatings were analyzed, and finally, by using open circuit potential techniques, electrochemical impedance spectroscopy, and Tafel polarization techniques, the corrosion resistance of the resulting coatings in 3.5 wt.% NaCl solution was evaluated. Microhardness and pin-on-disk tests were also utilized to investigate the effect of PTFE concentration on the tribological properties of the coatings. The results of scanning electron microscopy and energy dispersive spectroscopy studies confirmed the formation of nanocomposites. Electrochemical studies indicated that Ni-PTFE coatings at a concentration of 20 g/L PTFE exhibited the highest electrochemical corrosion resistance. Microhardness decreased as the amount of PTFE particles in the coating increased, reaching its lowest value. By using the wear test, the lowest coefficient of friction was obtained in composite coatings with a concentration of 20 g/L, which shows the applicability of PTFE particles as a solid lubricant in Ni-P coatings.