Effect of Surface Roughness and Particle Size on Lubrication Mechanisms of SiO2Nanoparticles

Abstract

In this study, a series of tribological tests were conducted on a pin-on-disc tester to study the lubrication mechanism of SiO2 nanoparticles under different surface roughness considering various loads and velocities. For a comprehensive understanding of the mechanism of SiO2 nanoparticles, base fluid was also employed as a contrast. Results show that the reductions of friction coefficients and wear scar widths increase with the decrease of surface roughness, due to the increase in rolling effect and self-repairing mechanism of SiO2 nanoparticles. The lubrication mechanism of SiO2 nanoparticles is the rolling effect when the height-diameter ratio () is less than 6, and the self-repairing mechanism at of 6 and 10, whereas, there is no obvious difference by adding nanoparticles when is 20. When the height-diameter ratio is less than 6, surface wears show an increasing trend as the load increases due to the high hardness of nanoparticles, while it is the opposite at of 10 and 20 because of the self-repairing mechanism.