Abstract: An organic compound coated copper nanoparticles with diameter about 1~7 nm were prepared and suppose to use as lube additive to reduce friction and wear as well as to increase load-carrying capacity. The tribological performance of this additive in HVIWH150 base oil and SJ 5W/30 gasoline engine oil was investigated by four-ball testing machine, respectively. Results showed that said nano-Cu additive could reduce wear and increase load-carrying capacity. When 0.1% nano-Cu additive was added into HVIWH150 base oil, the PB value of the formulated base oil was increased about 30%, and its wear scar diameter was decreased about 50%; SJ 5W/30 gasoline engine oil added 0.1% said additive, its friction coefficient was reduced about 28%. The analysis of the friction surface boundary film revealed that the improvement of antiwear and extreme-pressure properties of the formulated oil was due to the formation of a deposited film by copper nanoparticles having superior ductility.

Key words: nano-Cu, addtive, dispersion, stability, friction and wear behavior