Tribological studies on chemically modified rapeseed oil with CuO and CeO^sub 2^ nanoparticles

The environmental problems that are being caused by the mineral-based lubricants has prompted for exploring the possibility of using vegetable-based oil as a lubricant and this has become a worldwide trend. In the present study, the tribological behavior of the chemically modified rapeseed oil has been studied by using a four-ball tester. The CuO and CeO2 nanoparticles of size less than 50 nm were added to the chemically modified rapeseed oil ranging from 0.1 to 1 wt%. And the friction and antiwear properties were analyzed as per the ASTM standard D4172. The size of the nanoparticles was calculated qualitatively by using Scherrer equation with the help of X-ray diffraction analysis. Tribological results showed that the chemically modified rapeseed oil has good antiwear and friction-reducing properties than the raw rapeseed oil. The addition of oxide nanoparticles at an optimum concentration in the chemically modified rapeseed oil showed the good friction-reducing property nonetheless not good antiwear property. The surface topography of the worn ball surfaces was also studied by using a scanning electron microscope.