Investigations on Tribological Effectiveness and Tribo-Reactions of Non-edible Vegetable Lubricants with Polytetrafluoroethylene as Additives under AISI E-52100
摘要
The use of polytetrafluoroethylene (PTFE) nanoparticles as a lubricant additive has shown great potential in lowering friction, a problem encountered during machine operations. The PTFE tribological responsiveness in two distinct vegetable lubricants was examined in this work under steel material. The research began by assessing the physiochemical characteristics of the various vegetable lubricants, which are assumed to influence lubricant performance. Frictional analysis was conducted using the high-frequency reciprocating rig (HFRR) in terms of specific wear rate, coefficient of friction (COF), surface roughness, and wear scar diameter (WSD). Based on chromatographic research, neem possessed more unsaturated fatty acids than jatropha. It was found that the reference SAE−15W-40 performed slightly better than the two formulations. The frictional test shows that the lubricants operates better under higher operating frequency (7 Hz), although the difference was more pronounced with jatropha + 1 wt.% PTFE than with its neem + 1 wt.% PTFE counterpart. The COF and specific wear rate of base neem and jatropha were found to be 0.3169, 3.01 × 10−9 mm3/Nm, and 0.2801, 31.47 × 10−9 mm3/Nm, respectively, under 100 N and 7 Hz. The study discovered that neem’s higher concentration of unsaturated fatty acids with bent alkyl tails is the cause of its inferior tribological performance when compared to its jatropha counterpart. By using scanning electron microscopy and energy-dispersive spectroscopy to analyze wear, it was found that while PTFE additives were not very effective anti-wear materials, it creates a tribo-film that protected the sliding surface via a healing mechanism utilizing the frictional energy generated by the operation.