Effect Of Positive Peak Current And Sodium Tungstate On Friction And Wear Properties Of Micro-arc Oxidation Ceramic Layer On Aluminum Alloy

Aluminum alloys have a series of advantages such as low density,high specific strength,good molding and corrosion resistance,and low cost.However,low surface hardness,poor wear resistance,and easy damage are the bottlenecks in the application of aluminum and its alloys.The aluminum alloy micro-arc oxidation technology can be used to grow the ceramic layer with the base metal oxide as the main surface of the aluminum alloy with wear resistance,corrosion resistance and high temperature resistance,in this paper,6061 aluminum alloy is used as the object,and the surface of 6061 aluminum alloy is treated by micro-arc oxidation by controlling the positive peak current,micro-arc oxidation time and sodium tungstate concentration to investigate the positive peak current and tungstic acid.The effect of sodium content and micro-arc oxidation time on the thickness,surface roughness,microstructure,microstructure,hardness and friction and wear of the micro-arc oxidation ceramic layer.The results show that as the positive peak current increases,the thickness of the ceramic layer increases,the surface roughness increases,the number of micropores in the ceramic layer decreases,and the pore size increases.As the oxidation time increases,the thickness of the ceramic layer increases,the surface roughness increases,the micropores on the surface of the ceramic layer gradually become uneven,and microcracks on the surface are generated.As the content of sodium tungstate in the electrolyte increases,the thickness of the ceramic layer first increases and then decreases,and the surface microcracks increase.When the sodium tungstate is 2g/L,the thickness of the ceramic layer is the largest,and the breakdown voltage is generally good.In the micro-arc oxidation process,sodium tungstate participates in the reaction,and tungsten oxide is formed on the surface of the ceramic layer.The friction coefficient of micro-arc oxidation ceramic layer is positively correlated with the surface roughness and load of ceramic layer.With the prolongation of oxidation time,the roughness of the porous layer on the surface of ceramic layer is larger,but the friction coefficient is finally stable at 0.2,micro-arc oxidation ceramic layer.The wear performance is mainly related to the dense layer of ceramics;as the positive peak current increases,the wear resistance of the ceramic layer increases;as the content of sodium tungstate increases,the wear resistance of the ceramic layer increases,and the wear amount decreases.