| In recent years, with the rapid development of nanotechnology, nanomaterials as lubricant additives have begun to show their superiority. Therefore, more work about the effect of nano-materials on tribological behaviors should be done for the application technology. Up to now, the investigation on effect of nano-materials on tribological behaviors mainly focuses on surface nano-materials, because friction and wear are very sensitive to the structure and properties of the materials'surface. The preparation of organic-inorganic complex nanoparticles is causing more interest in science and industry. Now, a number of these nanoparticles have been studied as lubrication oil additive.SiO2/ZrO2 composition nano-power has excellently antiwear and extreme pressure performance, which owns the adding effect and cooperation effect of ZrO2 nano-particles and SiO2 nano-particles. As a new kind of lubricating oil additive, it is help for reducing coefficient of friction, antiwear, extending mechanical life and has the impotant ecnomy and application value.SiO2/ZrO2 composite nano-powders can effectively reduce energy consumption, reduce greenhouse gas emissions, save energy and protect environmental, which will play a dual role when his populary application as lubricant additives. It is a concept of sustainable development research under the guidance of low carbon economy. The development of new nano-lubricant additives, on the one hand it is a positive commitment to environmental responsibility, to complete the requirements of the national energy saving targets; the other hand it is to adjust the economic structure, improve energy efficiency, develop new industries, build an ecological civilization, achieve economic development and resource environmental win-win inevitable choice.In order to make further research of anti-wear and friction reduction mechanism, the author adopted to make SiO2/ZrO2 nano-composite powder by hydrothermal method and used the graft and situ surface modification method to change the surface of the composite nano-powder. We want to make SiO2/ZrO2 composite nano-powder from hydrophilic to lipophilic and have the dispersity and the suspended of the composite nano-powder in the basic oil. The main conclusions are reached as followed. 1. Produce SiO2/ZrO2 composite nano-powder: The best process parameters of the SiO2/ZrO2 nano-composite powder was obtained by the orthogonal test which studied the influence of the raw material of the ZrO2 nano-powder, the molar ratio of the SiO2/ZrO2and the hydrothermal temperature on the average size of the SiO2/ZrO2 nano-particle. The orthogonal test shows that the smallest of the nano-powder which the molar ratio of the SiO2/ZrO2 is 1:1 can be produced by using zirconium ethylic acid at the hydrothermal temperature of 200℃. In addition, the paper studied the impact of the calcining and hydrothermal method on the particles reunion. Transmission electron microscope testing(TEM), X-ray inflection, Scaning electron microscope(SEM), laser particle size analyzer, Zeta potentiometer were used to characterize the particles. The results indicate that there are much hydroxyl on nano-particles surface, the average grain diameter was 55nm, amorphous states and regular spherical shape of the SiO2/ZrO2 nano-composite powders were obtained by the hydrothermal method.2. Modification ofSiO2/ZrO2 nano-composite powder: In order to improve the oil-soluble of theSiO2/ZrO2 nano-composite particle, graft and situ surface modification were used. In the graft surface modification orthogonal test, the type of the surface modifiers, the content of the surface modifiers and the value of the pH were studied in the influence of the lipophilic of the SiO2/ZrO2 composite nano-particle. Transmission electron microscope (TEM), laser particle size analyzer, X-ray inflation, Scaning electron microscope, STA409EP integrated thermal analyzer, Zeta potentiometer were used to characterize the particles. The results indicate that the raw materal is zirconium ethylic acid, pH is 3, the content of the KH560 is 0.5wt% which is the optimal conditions, the molar ratio of the SiO2/ZrO2 is 1:1, which can change the surface of theSiO2/ZrO2 composite nano-particle from hydrophilic to lipophilic.In the situ surface modification orthogonal test,the relevance of the lipophilic and selection of modifier, the molar ratio of the SiO2/ZrO2,the type of the modifier and the molar ratio of the SiO2/ZrO2.The same methods in the graft surface modification were used to characterize the particles. The results show that the best modification was obtained in the condtion of zirconium ethylic acid, the molar ratio of the SiO2/ZrO2 is 1:2, the content of the KH560 is 0.3wt%. Moreover, the lipophilic of the stitu modified SiO2/ZrO2 nano-composite particle is better than the SiO2/ZrO2 nano-composite particle produced in the graft surface modification.3. Frictional wear property of SiO2/ZrO2 composite nano-powder: The friction reducing and anti-wear behavior of the SiO2/ZrO2 nano-composite used as additive in lubricant oil were analyzed by friction and wear test machine of MMU-10G.To four-ball test,the oil doped with 0.1wt% anti-wear additive that was modified with KH560 by situ modify method showed the best tribological properties among the tested oil samples.The reduction of the coefficient of friction was 13.81% compared with the base oil.To block-on-ring tribotester,the oil doped with 0.1wt% anti-wear additive that was modified with kh560 by situ modify method showed the best tribological properties.The reduction of the coefficient of friction was 16.09% compared with the base oil. SEM and XRD was used to analyze the inorganic repaired layer formed on the friction surface. Based on the Zr/Si elements of the additive are added into the surface. The additive has obvious anti-wear effect for the steel/steel friction pair. |
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