Tribological behavior of LaF3 nanoparticles as additives in poly‐alpha‐olefin

Abstract

PurposeThe purpose of this paper is to study the influences of test conditions to the tribological behavior of LaF3 nanoparticles as an additive to a polyalphaolefin (PAO).Design/methodology/approachAn Optimol‐SRV4 oscillating friction and wear tester (SRV) were used to investigate the tribological properties of LaF3 nanoparticles as an additive in a polyalphaolefin (PAO). The 3‐D morphologies and wear loss volume of the worn scar were measured using a surface profilometer. The chemical state and the intensity of La and F elements on worn surface after friction test was investigated with X‐ray photoelectron spectroscopy to interpret the possible mechanisms of friction‐reduction and anti‐wear with LaF3 nanoparticles.FindingsThe experimental results show that LaF3 nanoparticles added to PAO exhibit excellent load‐carrying capacity, anti‐wear and friction‐reduction properties. LaF3 nanoparticles deposited on the worn surface under lower test temperature during the friction test, and higher applied load, higher test frequency and longer test duration are propitious to the deposition of LaF3 nanoparticles accumulated on the rubbing surface. Under higher temperature, a complicated tribo‐chemical reaction occurred during the friction process, the tribo‐chemical reaction product of La2O3 deposit on worn surface, which also exhibits good lubricating performance.Originality/valueThis paper investigates the tribological properties of LaF3 nanoparticles as green oil additive in poly‐alpha‐olefin (PAO) under variable temperature, applied load, sliding speed and sliding duration. The results could be very helpful for the further applications of LaF3 nanoparticles additives in industry.