Tribological Investigation and Statistical Optimization by Response Surface Methodology of Vegetable Oil-Based Ionanolubricants

The demand for environmentally acceptable lubricants has surged due to awareness of the detrimental effects of petroleum-based lubricants. Vegetable oil-based nanolubricants have garnered significant attention over the past two decades. The present research work focuses on detailed experimental investigation of tribological and rheological characteristics of rice bran oil and sesame oil with trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ([P₆₆₆₁₄][BTMPP]) ionic liquid and titanium oxide (TiO₂) nanoparticles as additives. Experiments were conducted using ball on disc tribotester based on central composite design generated by response surface methodology. The study evaluated under three input parameters are load, speed, ionic liquid concentration and two output responses are average coefficient of friction and specific wear rate. Optimal tribological performance has been observed in rice bran oil and sesame oil formulations containing 0.608 vol% and 0.99 vol% of ionic liquid, respectively. Rheological analysis indicated Newtonian behavior across all lubricant samples.