Analysis of Anti-Wear Properties of CuO Nanoparticles as Friction Modifiers in Mineral Oil (460cSt Viscosity) Using Pin-On-Disk Tribometer

The present work investigated the anti-wear properties of CuO nanoparticles based mineral oil using pin-on-disk apparatus. The pin material selected was EN 24(untreated) as it is used in gear manufacturing. Commonly used graphite macro particles (wt.%) and CuO nanoparticles(wt.%) were used as additives. It had been observed that the additives based mineral oil samples exhibited superior antiwear properties than pure mineral oil. Both CuO nanoparticles (0.2 wt.%) and graphite (0.2 wt.%) based lubricant showed significant decrease in coefficient of friction and specific wear rate. There was a reduction in both coefficient of friction (28.5 % approx.) and specific wear rate (70 % approx.) in case of CuO nanolubricants and graphite based mineral oil as compared with the pure mineral oil.Flash-fire point, viscosity and viscosity index also increased with the increase in additive concentration. The surface characteristics of the pin were studied using Scanning Electron Microscope (SEM) and surface roughness tester. The SEM images showed more rough surfaces in case of pure mineral oil samples as compared with graphite and CuO nanoparticles based samples. The surface roughness values of the pins in case of graphite (0.2 wt.%) and CuO nano particles (0.2 wt.%) based lubricant were much lesser than pure mineral oil. From the results predicted minimum 0.2 wt.% CuO nanoparticles were required to enhance the antiwear property of the lubricant. This work aimed in bringing a comparative experimental analysis using CuO nanoparticles and commonly used graphite macro particles as lubricant additives on various properties such as viscosity, flash point, fire point, surface roughness and anti-wear properties. Thus, the work would be useful in developing new nano lubricants with minimum additive concentration.