Experimental study on the tribological properties of CuO-based biodegradable nanolubricants for machine tool slideways

Bio-lubricants are biodegradable and non-toxic. Bio-based lubricants are an attractive alternative to conventional mineral oil-based lubricants. This study deals with the tribological investigation of biodegradable nanolubricants which could be applied in machine tool slideways. The nanoparticle used was copper oxide (CuO) and the biodegradable oils used were coconut oil, sesame oil, olive oil, sunflower oil and soybean oil. The nanolubricants were prepared by adding 0.1% wt. of CuO nanoparticles in each biodegradable base oil. Experiments were conducted on a pin on block type reciprocating friction monitor and four ball tester. Friction, stick-slip and wear characteristics were analysed. The test results showed that the addition of CuO nanoparticles in biodegradable oils improve friction reduction and antiwear properties. The mechanism of friction reduction is found to be the formation of tribofilm through deposition of CuO nanoparticles on the wear surfaces. Field testing was conducted for the best nanolubricants.