Enhancing lubrication properties of glycerol by palladium nanoparticles as additives

Purpose This study aims to reduce the friction and wear of green lubricant glycerol by addition of nanoparticles. Design/methodology/approach Palladium nanoparticles (Pd NPs) with an average size of about 1.3 nm were synthesized in glycerol, which is used as both a solvent and reducing agent. The obtained colloid solutions containing Pd NPs were evaluated for their friction-reduction and wear-protection performance. Scanning electron microscope and X-ray photoelectron spectroscopy were used to analyze the morphology of wear track and surface chemistry of tribofilm, respectively. Findings The obtained colloid solution containing Pd NPs exhibited significant improvements in reducing friction and wear of glycerol. It is suggested that chemical conversion of glycerol, tribocatalyzed by Pd NPs, combined with deposit of Pd NPs on the wear track, formed a protective lubricating film that effectively minimizes friction and wear. Originality/value This study suggests that the Pd NPs are effective in enhancing lubrication performance of green glycerol, including a 75% reduction in friction coeficient and over 99% reduction in wear rate.