| The use of lubricating oil/grease is the main method to reduce friction and wear of gear parts of mechanical equipment and reduce energy consumption and environmental pollution.With the development of industrial technology,the requirement of friction reduction and anti-wear performance of gear lubricating oil/grease is increasingly higher.Due to the special effects,such as small size and high surface energy,nano-additives have been found to have good friction reduction and anti-wear properties.Therefore,the research on the effect of nano-additives on the friction reduction and anti-wear properties of gear lubricating oil/grease has important theoretical significance and application value for the development of new nano-additive gear lubricating oil/grease.The friction reduction and anti-wear properties of gear lubricating oil/grease containing nano-additives were studied by using the MRS-10A four-ball friction and wear tester,and the load-bearing capacity of gear grease with nano-additives was studied by FZG gear bench tester.By analyzing the friction coefficient,wear scar diameter,wear morphology,element distribution,chemical composition,etc.,the friction reduction and anti-wear properties and action mechanism of nano-additives were clarified.The main conclusions of this paper are as follows:（1）Sol-gel method was more suitable for coating spherical nano-additives with relatively uniform size.The Ti N@Si O2 composite nano-additive prepared by the sol-gel method could effectively improve the dispersion stability of 85W90 gear lubricating oil.The 85W90 gear lubricating oil containing Ti N@Si O2 composite nano-additive had the best effect when the mass concentration is 0.4 wt%,which could reduce the friction coefficient by 14.6%and the wear spot diameter by 23.2%.The comprehensive friction reduction and anti-wear performance of 85W90 gear lubricating oil were better than that of uncoated modified Ti N nano-additive.（2）The physical and chemical properties of gear grease containing WS2 and h-BN nano-additives could reach the required physical and chemical properties.The gear grease containing WS2 nano-additive had the best friction reduction performance when the concentration was 0.5wt%,which could reduce the friction coefficient and wear spot diameter by 17.3%and 11.5%and increase the maximum non-bite load by 20%.When the concentration of h-BN nano additive gear grease was 0.5wt%,the friction reduction performance was the best,and the friction coefficient and wear spot diameter could be reduced by 6.9%and 22.5%,respectively,and the maximum non-bite load could be increased by 20%.When the two kinds of nano-additives were mixed,the friction coefficient and the wear spot diameter could be reduced by 20.8%and 19.8%,respectively,when the concentration was 1wt%and the mixing ratio was WS2:h-BN=1:2.The effect was the best in such condition.（3）The load-bearing capacity of gear grease with nano-additive could reach 11 grades,which was higher than that without nano-additive.Nano-additive could significantly improve the load-bearing capacity of gear grease and had a polishing effect on the tooth surface,which could effectively reduce the wear of the gear meshing surface.（4）The nano-additive would participate in the chemical reaction to form a reaction film when acting on the friction surface,while the nano-additive which did not participate in the reaction mainly played the role of forming physical deposition film and ball bearing.Thus,it polila/ygered a sa e.role in enhancing the friction reduction and anti-wear properties of lubricating oil/grease. |
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