Influence of CuO Nanoparticles on the Tribological Performance of Karanja Oil ( <i>Pongamia pinnata</i> )

Abstract The environmental concerns associated with mineral oil lubricants have led to the exploration of vegetable oil‐based lubricants as a more sustainable and benign alternative. Nanolubricants have emerged as one of the innovative solution for producing improved friction reduction as well as better thermal and tribological performances. This research investigates the potential of karanja oil as a base lubricant, improved with copper oxide (CuO) nanoparticles as additives. Different amounts of CuO (ranging from 0.01% to 0.1% w/w) were introduced to karanja oil to form nanobiolubricants. These formulations were subsequently evaluated for their physiochemical and tribological properties, such as thermal stability by thermogravimetric analysis (TGA), kinematic viscosity, viscosity index, pour point, and anti‐wear characteristics following ASTM standards. Remarkably, even at low nanoparticle loadings, significant improvements in anti‐wear performance were observed. The study aims to elucidate the lubricating behavior of karanja oil when combined with CuO nanoparticles, revealing that these nanobiolubricants exhibit enhanced physicochemical and tribological properties, as well as improved thermal stability. These results emphasize the key role of nanoparticle concentration in optimizing the effectiveness of formulations.