Impact of various parameters on the tribological performance of nano lubricants considering oxide nanoparticles in conventional, semi-synthetic, and fully synthetic lube oils

Abstract

In the realm of lubrication, nanoparticles exert a notably positive influence on enhancing tribological performance, particularly certain oxide nanoparticles exhibit exceptional capabilities as friction and wear mitigators. However, a substantial research gap exists concerning the efficacy of oxide nanoparticles across various lubricant categories. Therefore, this study meticulously elucidates the effective integration of oxide nanoparticles in diverse lubricant categories. Using HRTEM, XRD, and FTIR, we characterize shape, size, and crystallinity. A Taguchi L18 orthogonal array is used for experimental planning, with performance characteristics of nano lubricants measured using four-ball testers. The experimental findings reveal a hierarchy of parameters governing the minimization of the coefficient of friction (COF), which are as follows: nanoparticle type, nanoparticle composition, load, speed, and lubricant, in that order. Similarly, the parameters controlling the reduction of wear scar diameter (WSD) are ranked as follows: load, nanoparticle composition, nanoparticle type, speed, and lubricant (base oil). Furthermore, an analysis of variance (ANOVA) is conducted to assess the contributions of these factors to COF and WSD. Regarding COF, 43.37% of the variance is attributed to nanoparticle type, 26.78% to nanoparticle composition, 14.49% to load, 11.8% to speed, and 2.36% to lubricant (base oil). In the case of WSD, the factor contributions are 47.67% for load, 22.4% for nanoparticle composition, 14.03% for nanoparticle type, 7.26% for lubricant (base oil), and 7.01% for speed.