Study On The Tribological Properties Of The Composite Nanoparticle Additives In Lubricating Oil

As lubricant additives, nano materials can play a role in friction reduction, anti-wear and self-repairing, which can improve the performance of lubricating oil and have a wide application prospects. Composite nano additives plays a feature of a variety of nanoparticles, and has more excellent tribological properties compared with single nanoparticles. It has become the future research trend of the nano lubricant. At this stage, there is lots of study on nano additives friction performance, but very few for the dispersion stability which is the main factors restricting the use of nanoparticles additives in lubricating oil. In addition, there is still insufficient research on the selecting appropriate type of nanoparticles and researching of the the composite nano additive tribological properties.In order to solve the above problems, the following experiments were carried out in this paper:(1) According to the principle of hydrophilic-lipophilic balance, mixing Span80 and Peregal OS-15 together to study the dispersing mechanism of the compound surfactant.(2) Select the low hardness and low melting point metal Nano Cu and the high hardness and high melting point nano Al2O3 nanoparticles as composite additives. By four-ball friction test, a detailed study on composite nano additive concentrations and ratios was carried out.(3) In reciprocating friction and wear testing machine, changing the loads and temperature continuously to study the effects of load and temperature to the composite additives, particularly in the high load and high temperature conditions. The experimental data and pictures were obtained from friction tester, metallographic microscope, scanning electron microscope (SEM) and electron energy spectrometer (EDS), and the mechanism of the composite nano additives was analyzed.The main conclusions of the experiment:The compound surfactant is applicable to different types and size of micro and nano particles and the dispersion performance is good. It provides feasibility for composite nanoparticles using in lubricating oil. Composite nanoparticle additive plays the best lubrication performance when the concentration is 0.5% and the ratio is Wtcu%:WtAl2O3%=60%:40%. Compared with the base oil, the wear resistance increases by 47.46% and the friction reducing performance increases by 28.62%. The nano composite additives plays a complementary and mutual coordination, the composite nano lubricating oil showed good anti friction and wear performance and repair performance. Under the complex working condition of high temperature and high load, the nano Cu and Al2O3 play a synergistic effect, The nano composite lubricating oil shows good performance in friction reduction and anti-wear.