Tribological Behavior of Reduced Graphene Oxide–Al2O3 Nanofluid: Interaction among Testing Force, Rotational Speed and Nanoparticle Concentration

Abstract

The tribological properties of nanofluids are influenced by multiple factors, and the interrelationships among the factors are deserving of further attention. In this paper, response surface methodology (RSM) was used to study the tribological behavior of reduced graphene oxide–Al2O3 (rGO-Al2O3) nanofluid. The interaction effects of testing force, rotational speed and nanoparticle concentration on the friction coefficient (μ), wear rate (Wr) and surface roughness (Ra) of steel disks were investigated via the analysis of variance. It was confirmed that all the three input variables were significant for μ and Wr values, while testing force, nanoparticle concentration and its interaction with testing force and rotational speed were identified as significant parameters for Ra value. According to regression quadratic models, the optimized response values were 0.088, 2.35 × 10−7 mm3·N−1·m−1 and 0.832 μm for μ, Wr and Ra, which were in good agreement with the actual validation experiment values. The tribological results show that 0.20% was the optimum mass concentration which exhibited excellent lubrication performance. Compared to the base fluid, μ, Wr and Ra values had a reduction of approximately 45.6%, 90.3% and 56.0%. Tribochemical reactions occurred during the friction process, and a tribofilm with a thickness of approximately 20 nm was generated on the worn surface, consisting of nanoparticle fragments (rGO and Al2O3) and metal oxides (Fe2O3 and FeO) with self-lubrication properties.

Triprotic Ammonium Oleate Ionic Liquid Crystal Lubricant for Copper-Copper Friction and Wear Reduction

“…This ionic liquid reduces both the running-in and the steady-state friction coefficient with respect to the base oils. The good tribological performance of MO is attributed to the formation of an easy shearing boundary layer, which also acts as an anti-wear and low-friction lubricant, reducing both friction and wear, particularly during the running-in period [24,25].…”

Using artificial intelligence to predict the tribology behavior of MoS2-Al2O3 hybrid nanofluid

“…diameter (D T ) and surface roughness of wear scar (Ra T ) for the 27 trials under different test conditions of were listed. However, the influence of multiple test parameters on the tribology behavior of lubricants is usually complex, especially for solid-liquid two-phase nanofluids [25]. The relationship between the various parameters describing the tribological performance is also intricate.…”

Analysis of TiO2 Nanolubricant Influence in Micro Deep Drawing of Stainless Steel SUS301

“…To further examine the potential of utilising NPs for this purpose, Wu et al [ 19 ] investigated the tribological behaviour of the lubricant with TiO 2 NPs and found that using the nanolubricant can effectively alleviate the overflow and reduce the friction in the steel-to-steel sliding process. As a result, subsequent research has been dedicated to exploring the correlation between the performance of the nanolubricant and the specific characteristics of the added NPs [ 20 , 21 , 22 , 23 ]. Furthermore, other researchers [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] have incorporated TiO 2 , SiO 2 , CuS, Al 2 O 3 , and MoS 2 NPs into liquid lubricants for application in metal rolling.…”