Abstract:The friction and wear prosperity of diesel soot and nanographite as lubricant additives in PAO4 oil was investigated by using ballplate reciprocating mode on the UTM-2 machine at different temperatures (25,100,175 ℃).The antifriction characteristics and lubrication mechanismwere analyzed by means of light microscopy,scanning electron microscopy,threedimensional morphology,and Raman spectroscopy.The result of AFM analysis displays that the particle size of diesel soot is between 20 nm and 70 nm,the nanographite,with particle size between 10 nm and 30 nm,is slightly smaller in particle size than the diesel soot.Diesel soot and nanographite of 0.01% in the lubricant play well antwear effect,which can reduce the friction coefficient by 50% to 80%,reduce the wear rate by 40% to 70%.The antiwear mechanism is that a protective film is formed on the worn surfaces by diesel soot and nanographite,which changes the frictional contact interface environment.