锆溶胶对铝合金微弧氧化过程的影响

摘要

Aluminum alloy was processed by microarc oxidation method with a control mode of constant current density in phosphate electrolyte with in­situ and additional zirconia sol. The effects of zirconia sol on the microarc oxidation process were investigated. The variations of voltage and electrolyte parameters, the growth process and surface microstructure of coatings were analyzed. The results indicate that in the electrolyte with in­situ zirconia sol, pH values reduce less, conductivity increases less, arcing voltage and electrolyte temperature are lower, and the growth rate of coating is higher, which is about 2.9μm/min. The ceramic layer obtained in electrolyte with in­situ zirconia sol is porous, the internal and external layers combine closely, the coating is thicker and the thickness is up to 85μm. The ceramic layer prepared in the electrolyte with additional sol includes more volcano­like deposits and is loose. The ceramic layer is mainly composed ofγ­Al2O3 and t­ZrO2 phases.%　　在原位锆溶胶和外加锆溶胶的磷酸盐电解液体系中，采用恒流模式对铝合金进行微弧氧化，通过分析氧化过程中电压和电解液参数的变化、氧化膜生长规律以及膜层表面形貌结构，研究锆溶胶对铝合金微弧氧化成膜过程的影响。结果表明，原位锆溶胶电解液氧化过程中pH值降低及电导率增加幅度较小，起弧电压、电解液温度较低，膜层生长速率较快，其厚度增长速率约为2.9μm/min。原位锆溶胶电解液制备的膜层表面呈多孔网状结构，内外膜层结合紧密，膜层较厚，可达85μm；外加锆溶胶电解液生成膜层表面有火山状沉积物，膜层疏松；微弧氧化膜主要由γ­Al2O3和t­ZrO2相组成。