On the Tribological Performance of Vegetable Lubricants: Experimental Investigation on Rice Bran Oil with Propyl Gallate

Due to the limited resources of oil-based lubricants and the increase in environmental pollution that they produce, there is a demand for biolubricants. For this reason, the purpose of this study is to investigate the tribological performance of rice bran oil in the lubricating contact pair of the AISI E52100 steel sliding against the Ti6Al4V titanium alloy. Experimental tests were carried out using an alternative ball-on-flat tribometer for two different frequencies, 10 Hz and 20 Hz and with a normal load of 13 N. Rice Bran Oil with propyl gallate, as an additive, was analyzed, as a novelty, for its chemical and physical properties such as viscosity, density, flash point, and tribological performance. The results of the tribological tests were interpreted on the basis of the evolution of the friction coefficient, the wear volume, the analysis of the surface topographies. The results of the Friction Coefficient obtained in the experimental tests reveal that as the frequency increases there is an increase in the Friction Coefficient values.