Investigation of Thermal and Tribological Behaviour of Oil Dispersed Oleic Acid-Functionalized CuO Nano-Particles in Gear Oil Nano-Lubricants

Nano-fluids are the new class of engineered fluids developed by dispersing nano-additives in base lubricants to enhance the thermal and tribological properties. In the present study, the CuO nano-fluids were prepared by dispersing oleic acid (OA) functionalized nano-particles in gear
 oil lubricants and have been tested for their performance evaluation in terms of friction, wear, and extreme pressure behavior. However, the effect of thermal conductivity on tribological performance at higher load was also investigated. The two-step method was used to formulate the CuO nano-fluids
 and OA was used as a surface functionalizing agent. Analytical techniques like FTIR, XRD, DLS, SEM, and EDX were used to investigate the characteristic properties of CuO nanoparticles. The sedimentation method and Induced Couple Plasma (ICP) technique were used to determine the dispersion
 stability of nano-fluids over 3 months. Further, KD2 Pro thermal conductivity analyzer was used to examine the thermal conductivity of nano-fluids. The findings reveal that the functionalized CuO nano-particles significantly improved the tribological properties of gear oil lubricants. Further,
 the enhancement in thermal conductivity reduced the contact temperature at a higher load and prevents seizure. The comparative assessments confirmed that CuO nanoparticles can be used as lubricant additives for gear oil lubricants.