On the Tribological Properties of RGO–MoS2 Composites Surface Modified by Oleic Acid

Abstract

Purpose To study the effect of oleic acid surface modi ed RGO/MoS 2 composite lubricating additives on the friction and wear properties of 10 # White Oil (10 # WO).Method The in uence of different concentrations of reduction graphene oxide/molybdenum disul de (RGO-MoS 2 ) and oleic acid surface modi ed reduction graphene oxide/molybdenum disul de (OA-RGO-MoS 2 ) on the lubricating properties in 10 # WO was investigated by using a four-ball long-term friction and wear tester. The microscopic morphology, lattice structure, composition and element valence of the prepared material were characterized by scanning electron microscope, Raman spectroscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, element analyzer and other instruments. The diameter, structure, morphology, composition and element valence state of the wear scar were obtained by multifunctional universal tool microscope, scanning electron microscope and X-ray photoelectron spectroscopy.Result In the RGO-MoS 2 white oil system, when 0.4 wt% RGO-MoS 2 was added, the anti-friction effect was the best, and the average friction coe cient (AFC) reduced by 21.8%. When 0.2 wt% RGO-MoS 2 was added, the anti-wear effect was the optimal, and the average wear scar diameter (AWSD) decreased by 12.4%. In the OA-RGO-MoS 2 white oil system, when 0.2 wt% OA-RGO-MoS 2 was added, the anti-friction and anti-wear effects were the best, and the AFC reduced by 33.3%, and AWSD reduced by 14.1%. ConclusionCompared with RGO-MoS 2 , OA-RGO-MoS 2 has a higher degree of graphitization, larger interlayer spacing, lower degree of layered accumulation, higher MoS 2 load, and weaker thermal stability.Both lubricating additives have good anti-friction and anti-wear effects at low concentrations, and the anti-friction and anti-wear effects are more prominent after being modi ed by oleic acid. Analysis of friction mechanism shows that a lubricating protective lm containing iron, oxygen, molybdenum, carbon, and sulfur is formed through adsorption or tribochemical reaction during the friction process, which improves the lubrication state and plays a role in reducing friction and anti-wear.

Self-dispersed molybdenum disulfide quantum dot/graphene crumpled ball as efficient high temperature lubricant additive

“…As shown in Fig. S2 in the ESM, peaks at 3,322, 1,637, and 678 cm -1 were corresponded to hydroxyl group stretching vibration, carbonyl group stretching absorption vibration, and methylene group bending vibration of GO, respectively [25,26]. Similar absorption peaks could be found for GCB, but the peak intensity was reduced due to the decrement of oxygen-containing functional groups during the reduction process [17].…”

MoS2 Nanomaterials as Lubricant Additives: A Review

“…For rGO/MoS 2 nanocomposites [127], when their concentration is low and their size is smaller than the oil film thickness, they can form interlayer slips between the friction interfaces and provide friction reduction. However, once the concentration is too high, the excess nanocomposites will agglomerate in the base oil, and this interlayer slip to reduce friction is more difficult to realize.…”

Tribological Behavior and Wear Protection Ability of Graphene Additives in Synthetic Hydrocarbon Base Stocks

“…In the past few decades, various new two-dimensional materials, including MXenes [6,7], MoS 2 [8,9], WS 2 [10], as well as graphene [11], have become a hot topic in the field of friction [12]. Among them, graphene has been widely considered by researchers due to its low surface energy and unique tribological properties [13][14][15] caused by easy-sliding multi-layer structures [16].…”