The effect of free fatty acids on the tribological properties of karanja oil

Abstract

Abstract Research is being carried extensively on vegetable-based lubricants to provide a suitable replacement against toxic and non-biodegradable petroleum-based lubricants. In this work, tribological properties of free fatty acids in non-edible karanja seed oil are evaluated. Free fatty acids namely palmitic acid, stearic acid, and oleic acid were added at 1%, 2%, 3%, and 5%by weight of the base oil. A four ball tribotester was utilized to study the friction and wear properties of different samples. These additives provided both anti-wear and anti-friction properties. Palmitic acid, stearic acid, and oleic acid reduced wear by 34.39%, 28.82%, and 13.12% respectively. Further, the coefficient of friction was reduced by 27.51%, 30.15%, and 44.97% respectively. The wear scar region was analyzed using optical microscopy. Flash temperature parameter (FTP) for different additives was calculated and found that at lower additive concentrations, stearic acid had a better FTP but at 5%wt., palmitic acid had the best FTP. Energy consumed during the test was calculated for different additive concentrations and oleic acid additive had the lowest energy consumption.