Study On Preparation And Tribological Properties Of MoS₂ And SiC Composite Micro Arc Oxidation Coating

Aluminum alloy has been widely used in the industrial field because of its small density and high specific strength.However,its surface hardness is low,and it is easy to wear and other defects,which limits the further development of aluminum alloy materials.So the surface strengthening treatment of aluminum alloy is of great significance.The ceramic coatings can be grown in situ on the surface of aluminum alloy by micro arc oxidation technology,and the coatings combined well with the substrate and has high hardness.Taking ZL109 aluminum alloy as an example,this paper studies the micro arc oxidation coatings of wear-resistant and friction reduction according to the deficiency of the tribological properties of aluminum alloy.In this paper,MoS2 and SiC two kinds of micro-nanoparticles were selected as electrolyte additives for composite micro arc oxidation coatings,and MoS2 as a wear-resistant additive,SiC as a friction reduction additive.After the two nanoparticles were well dispersed in the electrolyte and sintering in the micro arc oxidation coatings,the MoS2 and SiC composite micro arc oxidation coatings was successfully prepared.The structure,composition and tribological properties of the composite micro arc oxidation coatings were evaluated by scanning electron microscope(SEM),X-Ray Energy Spectrometer(EDS),hardness meter and friction and wear tester.In order to further improve the structure and tribological properties of the composite micro arc oxidation coatings of MoS2 and SiC,the concentration and ratio of MoS2 and SiC and the parameters of the experimental power were optimized.The results show that compared with the micro arc oxidation coatings without nanoparticles,the growth rate of MoS2 and SiC composite micro arc oxidation coatings slows down,the thickness of coatings is reduced by 16.2%,the surface is more dense and the roughness is reduced by 40.22%,and the hardness is increased by 11.06%.In friction and wear test,the wear amount of composite coatings is decreased by 32.65%,the friction coefficient is lower and stable,and when the concentration of nanoparticles is 6g/L,the content of two nanoparticles in the composite micro arc oxidation coatings was the highest,and the friction coefficient and wear amount were the lowest in the friction and wear test.When the total concentration of nanoparticles was 6g/L,under the condition that the compound ratio of MiS2 and SiC is 1:2,the friction coefficient of the composite micro arc oxidation coatings is lower the wear amount is the lowest,the effect of the composite micro-arc oxidation layer is obvious and the wear resistance is the best,and according to three indexes of coatings thickness,roughness and hardness,the optimization result of electrical parameters is forward voltage 450V,negative voltage 100V,the forward duty cycle is 30%,the negative duty cycle is 10%,the frequency is 800Hz,the thickness of the film layer is greatly improved after the electric parameter is optimized,and the roughness and hardness of the film layer also improve slightly.