Investigation on lubricity effectiveness ficus carica lubricant modified with PTFE and TBHQ as additives for steel-steel contact application

The application of additives to the bio-lubricants is essential to improve the base oil tribological properties. A high-frequency reciprocating rig and different operating conditions were used to test the effects of tert-butylhydroquinone (TBHQ) and polytetrafluoroethylene (PTFE) polymer on the tribological performance of ficus carica oil as a base oil for machine lubrication. The viscosity and Fourier transform infrared spectroscopy (FT-IR) evaluations were carried out to ascertain the additive's effectiveness. A scanning electron microscope was used to analyse the morphologies and the substrate-worn surfaces. When additives were applied separately, 1wt.% of PTFE produced a superior coefficient of friction (COF) and better wear reduction than other examined samples. In terms of wear resistance, commercial lubricant oil (CLO) SAE 5W-30 performed better than the optimal 1wt.% PTFE + 0.3wt.% TBHQ blended with ficus carica oil (FCO/L). At an increased frequency of 5Hz, CLO outperformed FCO/L on COF and wear resistance. When examining the worn surfaces, less iron (Fe) was discovered on the FCO/L than the base ficus carica oil, demonstrating the mending effect of the used additive as the underlying mechanism of wear reaction. The results show promising potential for the new formulation of a green lubricant since the tribological characteristics of ficus carica oil were improved by the addition of the selected additives.