Evaluation of tribological properties of vegetable oil-based ionanolubricants: An experimental study

Growing environment concern has forced us for the development of environmentally acceptable lubricants. In this study, tribological properties of sesame oil and castor oil containing imidazolium-based ionic liquid 1-ethyl 3methylimidazolium dicyanamide ([EMIM][DCN]) (IL1), phosphonium-based ionic liquid Trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ([P-66614][BTMPP]) (IL2) and titanium oxide (TiO2) nanoparticles (NPs) as hybrid additives have been investigated using four-ball tester with ASTM D4172B. Three different concentrations of IL1, IL2 and TiO2 NPs were selected for the formulation of vegetable oil-based ionanolubricants. It was found that castor oil with the addition of 0.03 null of TiO2 NPs and 1.3 vol.% of IL1 shows the lowest specific wear rate amongst all investigated lubricant samples. It is evident from field emission scanning electron microscopy analysis of worn-out surfaces of steel balls that a combination of ball bearing effect and tribofilm formation is responsible for the improved tribological characteristics.