| Lubricating Anti-Friction Coating can solve the problems of poor corrosion resistance,poor lubricating effect and high wear of the base material.It improves the accuracy and life of the workpiece,attracteding more and more attention.At present,the solid lubricant molybdenum disulfide(MoS2)lubricating anti-friction coating is most widely used due to its advantages of good thermal stability,low shear strength,low friction coefficient and strong surface adhesion,but it is produced under high-speed wear A large amount of frictional heat will destroy the organic matter in the coating,destroy the continuous integrity of the coating,and accelerate the wear of the coating.Therefore,the wear resistance and thermal conductivity of the MoS2 lubrication anti-friction coating still need to be further improved.In order to achieve the purpose of improving the wear resistance and thermal conductivity of the coating at the same time,this article combines the phosphating process and the doping modification to prepare hard particles(spherical Al2O3)and thermally conductive agent(colloidal graphite)on the surface of the aluminum alloy substrate.The complex MoS2 composite coating finally obtains a lubricating anti-friction composite coating with excellent wear resistance and thermal conductivity.The specific method is as follows:(?)The solution impregnation method is used to phosphatize the aluminum alloy substrate,and the influence of the phosphating film on the corrosion resistance of the substrate and the binding force of the MoS2 coating film substrate is studied;(?)MoS2/spherical Al2O3 and MoS2/spherical Al2O3/graphite composite coatings were prepared by spray coating.The effects of hard particle doping and hard particle+thermal agent co-doping on the microstructure and friction and wear properties of the composite coating were studied,and determine the best formula for composite coatings under high-speed wear.The results of the study indicate that a continuous and uniform porous phosphating film can be prepared by the phosphating process.The pore size of the aluminum alloy zinc-based phosphating film is about 1 ?m,with the highest porosity,which can greatly increase the contact area between the aluminum alloy substrate and the MoS2 coating.At the same time,the destruction time of the phosphating film is about 45 s,and the phosphating film has the best corrosion resistance.The composition of MoS2/spherical Al2O3 composite coating prepared by air spray method is uniform.The diameter of spherical Al2O3 is about 3-5 ?m.It is evenly dispersed inside the coating without agglomeration.The composite coating is less microscopic than the undoped MoS2 coating.The hardness is increased by about 240%,the friction coefficient is reduced by about 18%,the width of the wear scar becomes smaller,and the wear resistance is significantly improved.The thermal conductivity and microhardness of the MoS2/spherical Al2O3/C composite coating prepared by colloidal graphite and spherical Al2O3 co-doping modification are significantly improved,and the synergistic effect of hard particles and thermal conductivity agent significantly improves the friction and wear performance of the MoS2 composite coating.Under the condition of high-speed wear(560 rpm),the composite coating with a mass ratio of 6:2:3 has the best tribological performance.The friction coefficient is about 60%lower than that of the MoS2 coating,and the wear scar cross-sectional area is reduced by about 40%.The performance is significantly improved.Due to time reasons,this article does not systematically characterize the fatigue life and thermal conductivity of MoS2 lubricating anti-friction coatings,and there is insufficient research on the contribution of improved thermal conductivity to the friction and wear properties of MoS2 lubricating anti-friction coatings. |
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