Ionic liquid lubrication of electrodeposited nickel–Si3N4 composite coatings

Nano-Si3N4 particles were electrodeposited with nickel on copper substrate from a Ni bath. The friction and wear properties of the Ni/Si3N4 composite coating were evaluated while being lubricated with several various oils using a ball-on-disk sliding tester. The morphologies of the worn surfaces were observed using a scanning electron microscope. The chemical states of several typical elements on the worn surfaces were examined by means of X-ray photoelectron spectroscopy (XPS). Results indicated that the electrodeposited Ni/Si3N4 composition coating had excellent tribological properties while being lubricated with the ionic liquid. This was partly attributed to the high hardness of the electrodeposited nickel composite coating containing nano-sized Si3N4 and the tribochemical reaction between the lubricant and the sliding surface.