Tribological investigation of organic compound-coated nano-copper as lubricating oil additive

Organic dithiophosphate-coated copper nanoparticles with ∼ 5 nm dia were prepared. The tribological performance of this nano-Cu as additive in both HVIW H150 base oil and 5W30SJ gasoline engine oil were studied. When Cu nanoparticle was added to HVIW 1-1150 base oil and 5W30SJ gasoline engine oil, it could effectively increase P_B values and P_D values of the oils, showing good EP ability. When the dose added to 5W30SJ gasoline engine oil was 0.4%, it could effectively increase P_B value of oil, showing fair EP ability in formulated oil. Only when the addition dose of nano-Cu additive of 0.8%, it could effectively decrease friction coefficient of the mineral base oil. Different from the results of mineral base oil, nano-Cu additive could markedly decrease friction coefficient when added to 5W30SJ gasoline engine oil in different dose. When nano-Cu additive was added to HVIW H150 base oil at low dose such as 0.1%, it could markedly increase the oxidation induced time of the mineral oil. Friction and wear tests results proved that the as-prepared nanoparticles as oil additives have excellent friction-reducing and antiwear properties. Nano-Cu additive (0.1%) had no harmful effect on the main performance of 5W30SJ gasoline engine oil, but could reduce friction and wear. This is an abstract of a paper presented at the 11th Annual Fuels and Lubes Asia Conference (Beijing, China 3/15-18/2005).