电流密度对AlSi7Mg0.3铝合金微弧氧化陶瓷层性能的影响

Effect of current density on characteristics of the micro-arc oxidation ceramic coating on AlSi7Mg0.3 aluminum alloy

以采用微弧氧化技术在AlSi7Mg0.3铝合金表面制备的陶瓷层为研究对象,利用XRD和SEM等手段分析了陶瓷层的相组成及表面形貌,探讨了电流密度对成膜速率、膜层结构的影响,借助拉伸实验研究了陶瓷膜与基体的结合强度.研究结果表明:电流密度过大会使陶瓷层成膜速率加快、表面质量下降、结合力降低;微弧氧化陶瓷层主要由γ-Al_2O_3、α-Al_2O_3和少量Al_2(SiO_4)O组成,电流密度的变化会导致陶瓷层内γ-Al_2O_3和α-Al_2O_3的含量变化,在一定范围内,电流密度越高,γ-Al_2O_3的含量越多,陶瓷层性能越好;陶瓷层界面结合强度随着电流密度增加而增加,但过大的电流密度反而导致界面结合强度减小.

It takes ceramic coatings prepared on AlSi7Mg0.3 aluminum alloy by micro-arc oxidation technique as the study object in this paper, then the phase compositions and surface mor- phologies of ceramic coatings under different current densities are analyzed using XRD and SEM techniques, the effects of different current densities on the rates of ceramic coating formation and the structures of ceramic coatings are discussed, and the interracial bonding strength between ce- ramic coatings and AlSiTMg0.3 aluminum alloys is studied by means of tensile tests. The results show that the rate of ceramic coating formation will increase, and the surface quality and the interracial bonding strength will decrease if current density is too high. The micro-arc oxidation ceramie coatings are mainly composed of γ-Al2O3, α-Al2O3 and a small amount of Al2 （SiO4） O, and the change of current density will change the contents of γ-Al2O3, α-Al2O3. The content of γ-Al2O3 will increase and the characteristics of ceramic coating will improve when current density increase in a certain range. In addition, the bonding with the increase of current density, but excessive current terfacial bunding trength. strength of density will ceramic coating increases lead to the decrease of in-