Preparation And Tribological Properties Of SiC Composite Micro Arc Oxidation Coating

Aluminum alloy plays an important role in the light weight development of large machinery.However,its low surface hardness and poor wear resistance restrict its wide application.As a surface strengthening technique with good adhesion and high surface hardness,micro arc oxidation has made up the deficiency of aluminum alloy.Taking ZL109 aluminum alloy as the research object,this paper explores the process of micro arc oxidation under the two power modes of constant voltage and constant current,and adds nano particles SiC to the electrolyte to prepare the composite micro arc oxidation layer containing SiC.Through the detection and analysis of the film thickness,roughness,hardness,elemental composition,phase composition and surface morphology,the tribological properties of SiC composite micro arc oxidation layer were explored,and the tribological properties were explored.The results show that the preparation process of constant voltage micro arc oxidation layer is relatively mild,the thickness of oxide layer is small,and the surface roughness is low.The preparation process of constant current micro arc oxidation layer is intense,the stable phase a-Al2O3 is relatively increased,and the hardness is higher.The existence of SiC was detected in the constant voltage SiC composite micro arc oxidation layer and the constant current SiC micro arc oxidation layer,and the constant current mode is more conducive to the SiC particles entering the micro arc oxidation layer.Compared with the blank group without adding SiC particles,SiC composite micro arc oxidation layer hardness increases,the constant current SiC micro arc oxidation layer reaches more than 1500HV;the friction and wear experiments,adding composite coatings formed by micro-arc oxidation of SiC under dry friction condition showed lower wear loss,constant pressure SiC composite coatings in dry friction and fuel lean conditions exhibit lower friction coefficient,while the constant current SiC composite micro arc oxidation layer exhibited lower wear quality.