Experimental study on the lubricating and mechanical properties of grapheme nio coconut oil hybrid nanofluid

Abstract

The lubricants are generally used to minimize the friction and wear of frictional surfaces. The disposal of mineral based lubricating oil possesses environmental issues and leads to the development of biodegradable lubricating agents. Existing studies show that the simultaneous mono-dispersion of metallic and metal oxides nanomaterials into lubricating agents may concurrently reveal superior thermo-physical and rheological characteristics of base lubricants. The present research makes an experimental and theoretical investigation on the lubricating and mechanical properties of Graphene/NiO-Coconut oil hybrid nanofluids. The Graphene with the average sheet size of lt2 and#956;m and a thickness of 1-4 nm and NiO nanomaterials is used as a bio lubricant additive. The NiO nanomaterials are chemically synthesized through the sol-gel technique. The Scanning Electron Microscope (SEM) micrographs of Graphene show flat platelet texture which has 3-8 Graphene of approximately 3-5 nm height per layer and are agglomerated due to surface energy. Different weight fractions of Graphene-NiO/Coconut oil hybrid nanofluid are formulated by using two-step method. Firstly, the Graphene/NiO hybrid nanomaterials in the ration of 70:30 are added simultaneously into Coconut oil and mixed using a magnetic stirrer for 3 hours. In the next step the samples are sonicated for 3 hours for obtaining homogenized dispersions and their dispersion stability is estimated by sedimentation method. The characteristics of lubricants differ when dispersed with nanoparticles at different concentrations, which reduces the asperity interaction in hydrodynamic, elasto-hydrodynamic and boundary lubrication regimes. newline