Wear behavior of carbon steel electrodeposited by nanocrystalline Ni–W coating

Abstract

Ni-W coatings, compared to pure nanocrystalline Ni, exhibit higher hardness and wear resistance. In some cases, these coatings are considered as environmental friendly alternatives for hard chromium coating. Till now, most of Ni-W coatings have been produced by direct current electrodeposition from alkaline baths. In this study square pulse current was used for deposition of Ni-W precipitates fromWattsbath. The effect of current density and duty cycle on morphology and wear behavior of nano-structured Ni-W coatings was investigated .The structure and morphology of the coatings were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. Mechanical and tribological properties of the deposits were also investigated by means of microhardness and pin-on-disk wear tester. The results showed that a decrease in current density and duty cycle increased the W content of Ni-W coating. This increase led to an increase in hardness and improved the wear resistance of nanocrystalline coatings.