Abstract The free-cutting Al-Cu-Pb-Bi alloy AA2011-T3 has been anodized in a traditional sulphuric bath with the aim of producing hard and uniform oxides of technological interest. H2SO4 concentration, electrolyte temperature, Al3+ concentration and current density have been modified. The effect of each process parameter has been evaluated through Potential-vs-time plot, coating hardness, coating thickness, volumetric expansion-ratio and coating defectiveness. SEM analysis has shown that Bi-based intermetallics are the main responsible for the severe defective state. Higher H2SO4 concentration and higher current density have improved coating hardness and defectiveness, however potentiodynamic polarizations have revealed that they do not enhance corrosion resistance.

中文翻译：

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AA2011-T3 Al-Cu-Pb-Bi 易切削合金的硬质阳极氧化：工艺参数的改进

摘要 易切削的 Al-Cu-Pb-Bi 合金 AA2011-T3 在传统的硫酸浴中进行了阳极氧化，目的是生产具有技术意义的坚硬且均匀的氧化物。H2SO4 浓度、电解液温度、Al3+ 浓度和电流密度已被修改。每个工艺参数的影响已通过电位-时间曲线、涂层硬度、涂层厚度、体积膨胀比和涂层缺陷进行评估。SEM 分析表明，Bi 基金属间化合物是造成严重缺陷状态的主要原因。更高的 H2SO4 浓度和更高的电流密度改善了涂层硬度和缺陷，但是动电位极化表明它们并不能提高耐腐蚀性。