Friction and wear properties of base oil enhanced by different forms of reduced graphene

Jankhan Patel,Gavin Pereira,Amirkianoosh Kiani,Doug Irvine

doi:10.1063/1.5089107

Abstract

In this study, the tribological effects of three different forms of reduced graphene oxide (rGO)-2D nano-additives in base oil were investigated. Reduced graphene oxide nanoplatelets were manufactured using a modified Hummers’ method. However, different filtration methods were used to obtain rGO nanoplatelets at three different bulk densities. After adding nano-additives to the base oil at 0.01%w/w concentration, physical and chemical characterization tests were performed such as viscosity test, four-ball wear test, rotating pressure vessel oxidation test (RPVOT), resistivity test and friction coefficient test. The presented results show that material-1 with the lowest bulk density and less lattice defect can perform better by reducing wear of the material by 10.63% as well as the coefficient of friction (COF) by 6.3% with respect to the base oil and under test conditions. The presented results show the promising effect of rGO as nano-additives to fluid lubricants on wear preventive properties without compromising the physical and chemical characteristics of the lubricants.

Highlights

Statistics exhibit that 23% of global energy is consumed to overcome friction between mating surfaces and to remanufacture the worn parts.1 Industries are increasing alignment capability and controlling stress fluctuation by introducing different types of bearings; historical data proves that 90% of bearings fail prematurely due to insufficient lubrication capability.3 To mitigate this problem, the proper lubricant needs to be applied to the contact surfaces, which can provide low shear strength film and eliminate direct contact between surfaces.2Lubricants are classified by their material states such as liquid, gaseous, solid, or semi-solid
To differentiate rGO based on crystalline defects and size, and degree of hybridization, Raman spectroscopy was employed to obtain the D and G bands for the three forms of reduced graphene oxide
RGO demonstrates an effective wearresistive property by reducing the wear of a steel ball substrate under 147N load by 10.63% compared to the base oil

Summary

Introduction

Statistics exhibit that 23% of global energy is consumed to overcome friction between mating surfaces and to remanufacture the worn parts. Industries are increasing alignment capability and controlling stress fluctuation by introducing different types of bearings; historical data proves that 90% of bearings fail prematurely due to insufficient lubrication capability. To mitigate this problem, the proper lubricant needs to be applied to the contact surfaces, which can provide low shear strength film and eliminate direct contact between surfaces.2Lubricants are classified by their material states such as liquid, gaseous, solid, or semi-solid. Industries are increasing alignment capability and controlling stress fluctuation by introducing different types of bearings; historical data proves that 90% of bearings fail prematurely due to insufficient lubrication capability.3 To mitigate this problem, the proper lubricant needs to be applied to the contact surfaces, which can provide low shear strength film and eliminate direct contact between surfaces.. It is important to enhance the properties of a lubricant, such as shear life, range of viscosity and the behavior under extreme pressure, and to maintain important properties such as friction and wear control. To address these challenges, researchers have proposed various advanced materials to improve lubricant performance by amalgamating nanomaterials such as carbon nanotubes (CNTs), fullerene and graphene.. Chemical, thermal or irradiation (UV or IR) methods are used to reduce graphene oxide into rGO form

Methods

Results

Conclusion