Tribological Experimentations with Jatropha Biofluid and Nanoparticles as Lubricant Additives

The use of vegetable oils as lubricants in automobiles is rapidly increasing due to the prevailing environmental aspects. Vegetable oils are also suitable for other applications because they come from renewable and sustainable natural sources and have high biodegradability and low toxicity. Nanoparticles have been extensively investigated for a long time as potential performance improvers of traditional antifriction and antiwear additives because of their inherent properties such as size and shape. The primary aim of the study is to investigate the use of jatropha oil mixed with graphite, molybdenum disulfide (MoS2), and titanium dioxide (TiO2) nanoparticles as a nanoparticle biolubricant. The nanoparticles of graphite, molybdenum disulfide, and titanium dioxide are added in varying weight percentages to jatropha oil and a tribological analysis is carried out using a pin-on-disc tribometer. The analysis is focused on tribological quantities, such as coefficient of friction, wear volume, and frictional force. The experiment was carried out for 5 minutes under varying loads at different disc speeds. At an optimum concentration of nanoparticles, the coefficient of friction, frictional force, and the wear rate were found to have the lowest values, but when the level of nanoparticles increases above the optimum level, the friction coefficient and wear rate seem to be increased. The pin-on-disc experiments revealed that nanographite powder mixed in jatropha oil gives better tribological performance than the other two tested nanopowders. Subsequently, multiple regression models are developed using input and output variables. A non-linear fit between the response and the corresponding significant parameters is considered