Studies on the electrodeposition and characterization of PTFE polymer inclusion in Ni–W–BN nanocomposite coatings for industrial applications

Abstract

A Ni–W–BN–PTFE nanocomposite coating with excellent corrosion and friction resistance alongside hardness and a smooth surface was developed. This was achieved by introducing polytetrafluoroethylene (PTFE) polymer to an optimized Ni–W–BN nanocomposite coating deposited on a mild steel substrate by direct current (DC) and pulse current (PC) methods. The deposition was characterized using field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX) and X-ray diffractometry (XRD). The microhardness and friction resistance of the coatings were measured by using a Vicker’s microhardness tester and a TR-101-M4 scratch tester. The contact angle (CA) of a water droplet on the surface of the nanocomposite coating was measured by optical contact goniometry (OCA 35). The corrosion behaviour was measured using Tafel polarization and impedance methods in 3.5% NaCl solution. It was observed that the co-deposition of PTFE solid lubricant particles on the Ni–W–BN nanocomposite coating resulted in a comparatively smooth surface, higher microhardness, a lower friction coefficient, excellent water repellency and enhanced corrosion resistance. The PC method showed enhanced performance over the DC coating due to uniform and smaller grain deposits.