Role of base oils in developing extreme pressure lubricants by exploring nano-PTFE particles

The suitability of various basestock oils based on classification by American Petroleum Institute (API) as Group I, II, III and IV with polytetrafluoroethylene (PTFE) nano-particles (NPs) as extreme-pressure additive (EPA) in oil was investigated. The nano-lubricants (NLs) with 3% NPs of PTFE (≈230 nm) were evaluated for their physical and tribological performance along with an in-depth studies on the stability aspects. The worn surfaces were examined thoroughly to analyse the mechanisms. Group I based NL, showed the highest weld load (620 kg) with 288% improvement. This was attributed to synergistic chemical action of PTFE NPs and Sulphur (in the base oil) with the base metal surface to form a stable and robust tribo-film. •Right selection of a base oil for developing efficient EP-oil with PTFE nanoparticles (NPs).•NPs proved excellent as EPA (300% improvement).•Very good stability of developed oils confirmed from UV–Vis spectra.•Synergism between PTFE and Sulphur to form a robust tribo-film of FeF2, FeS.