Friction reduction properties of a CuO nanolubricant used as lubricant for a NiCrBSi coating

This work presents and discusses the friction behaviour of a NiCrBSi coating lubricated by CuO nanoparticle suspension (nanolubricant or nanofluid) in a polyalphaolefin (PAO6). CuO nanoparticles were separately dispersed at 0.5 and 2.0 wt% in PAO6. Friction reduction properties were obtained using a block-on-ring tribometer, where blocks were coated with a NiCrBSi alloy using the laser cladding technique. Tests were made under loads of 165 and 214 N, sliding speed of 0.5 m/s and a total distance of 1800 m. Worn surfaces on blocks were characterised by EDS and XPS. The study led to the following conclusions: all nanolubricants tested exhibited reductions in friction compared to the base oil; the antifriction behaviour of the nanoparticles on the wear surfaces can be attributed to third body and tribosinterization mechanisms proved by EDS and XPS results, respectively.