Improving thermal and tribological properties of enhanced biolubricant with graphene and maghemite nano-additives

Abstract

Failure of biolubricants at elevated temperature hinder their efficient performance. These challenges are ameliorated using nano-additives to enhance the thermal and anti-wear properties of lubricants. In this study, coconut oil as base fluid was dispersed with 0.1% volume concentration of maghemite (γFe2O3) and exfoliated graphene (XGnP) nano-additives. Thermogravimetric analysis (TGA) was performed using thermal analyser to evaluate thermal degradation of nanolubricants and the base oil. In addition, anti-wear properties and viscosity of base coconut oil and the enhanced nanolubricants were evaluated. The TGA results indicates that oxidation onset temperature was retarded by 9 ℃ and 31.82 ℃ for maghemite (MGCO) and graphene (XGCO) enhanced nanolubricants respectively in comparison with base coconut oil (CCO). Friction reduction and anti-wear property of the nanolubricants showed better performance over the base oil. For graphene enhanced nanolubricant, a reduction of 10.4% and 5.6% in terms of COF and WSD respectively was observed while 3.3% and 4.3% reduction in COF and WSD respectively for maghemite enhanced nanolubricant when compared with the base oil (CCO). The excellent property improvement of thermal stability and tribological properties makes the enhanced lubricants a suitable candidate for consideration as machining lubricants.