Study On Metal Nanoparticles As Lubrication Oil Additives

The service performance of lubrication materials are determined by lubrication additives to a great extent,rational design of lubricating oil can meet the needs of machine and parts about anti-wear and friction reduction.Developing lubricating oil additive with good anti-wear,high load-bearing capacity and self-repair of wear surface is one of the most important questions in tribology.Due to its special properties,nanoparticles have been prepared and tested as additives of lubrication.In this thesis,preparation methods,surface modifications and tribological properties of metal nanoparticles as lubrication additives have been studied.With the reference of many relevant materials,by adopting chemical methods,nickel nanoparticle and copper nanoparticle were prepared.Those metal nanoparticles were modified with oleic acid to improve their dispersive properties,so as to find out optimum temperature of nano-Ni is 65℃,optimum dosage is 0.75%,the best time of surface modifications is 2.5h,and optimum temperature of nano-Cu is 60℃, optimum dosage is 0.5%,the best time of surface modifications is 2h.By using XRD and SEM,nano-Ni and nano-Cu were characterized.The results verified that nano-Ni and nano-cu prepared above are FCC,and their average particle size are 40nm and 20nm;Tribological performances of nickel nanoparticles and copper nanoparticles as additives in F4008 marine lubricating oil were researched by friction and wear tester as well.After measuring wear spot diameter,friction coefficient,weight difference of test samples,the relationship between these data and the variations of concentration of nickel nanoparticles and copper nanoparticle was analysised,the optimum concentration range of nano-Ni is 0.4%～0.6%,nano-Cu is 0.9%～1.1%were obtained.Another experiment was adding nano-Ni concentration 5%,nano-Cu concentration 1.0%as additives in F4008 maritime lubricating oil,studied anti-wear and friction reduction properties in different load conditions.Especially when the load was 500N,the slope of friction coefficient,wear spot diameter and wear loss curve were approaches 0.It shows that the anti-wear effects of nano-Ni and nano-Cu in high load condition is more obviously than other load conditions.