Nanoparticles as lubricant additives

Nanoparticles were prepared by a chemical surface modification method. The synthesized nanoparticles could be well dispersed in some organic solvents and liquid paraffin base stock as well as in formulated engine oil. Due to the modification effect of organic compounds around the surface of nanoparticles, the oxidation of nanoparticles was thus prevented. Under boundary lubrication conditions, organic-inorganic nanoparticles as additive in lubricant exhibited good antiwear and friction-reduction properties. The dispersion of liquid paraffin, mineral oil, and engine oil plus organic-inorganic nanoparticles, lubricated effectively steel-on-steel system at a very low concentration. Tribochemical reactions took place for organic-inorganic nano-Cu, with the formation of a boundary film containing elemental copper, which gave high load-carrying capacity and good antiwear ability. The addition of 0.05 or 0.10 wt %, nano-Cu to engine oil, a remarkable reduction of wear scar diameter and friction coefficient could be observed, illustrating that nano-Cu particles are quite effective to enhance the performance. This is an abstract of a paper presented at the 10th Annual Fuels and Lubes Asia Conference (Shanghai, China, 3/2-5/2004).