An Experimental Investigation of the Impact of Nanoparticles on the Tribological Properties of 15w40 Lubricating Oil

The objective of this research is to investigate the effect of various nanoparticles (SiO2, WS2, Cu, CuO and graphite) on the tribological properties of 15W40 Lubricating oil. The nanoparticles blended in the lubricant homogenously using magnetic stirring and ultrasonication, surfactant was used in the case of Cu and CuO nanoparticles to enhance the stability of nanolubricant. The tribological testing of the nanolubricant was carried out on four ball tester according to ASTMD4172 for wear preventive characteristics of the lubricant and ASTMDIN 5135002 for extreme pressure test of liquid lubricant. The experimental analysis showed that the coefficient of friction (COF) and wear scar diameter (WSD) reduced by using the nanoparticles in the lubricant. The reduction of COF is maximum in case of SiO2 nanolubricant 15%-25% followed by graphite nanolubricant ≈15%-18%, WS2 nanolubricant ≈13%-21% and Cu nanolubricant ≈9%-20%, CuO showed minimum reduction in COF ≈1.5%-17%. The reduction in WSD in case of SiO2 nanolubricant ≈50%-59%, graphite nanolubricant ≈45%-57%, WS2 nanolubricant ≈17%-26%, Cu and CuO showed ≈33%-49% and ≈13%-28% respectively. The percentage increments in the weld load were maximum in case of CuO nanolubricant ≈29%, followed by WS2 nanolubricant ≈27%. In case of Cu nanolubricant, SiO2 nanolubricant, Graphite nanolubricant improvement is about ≈22%, 11%, 19% respectively.