Magnesium alloy AZ31 is a light material with a good mechanical stability and is used in various engineering applications. Although its tendency to localized corrosion is a limiting factor in its use. Electropolishing is a widely used process for improving the surface roughness and corrosion behavior of metals. However, there is a lack of knowledge about the electropolishing of magnesium and its alloys. In this study, an optimal electropolishing process for AZ31 was developed to improve the surface properties by varying the electrolyte concentration and the applied potential. The electrolyte composition was a mixture of phosphoric acid, ethanol and deionized water. The applied potentials were selected based on measured current density potential curves. Thereby, electropolishing was performed up to an electric charge of 18 As. The experimental results indicate that the electropolishing process should be carried out at a low current density to avoid bubble evolution and surface defects. Therefore, the concentration of the electropolishing electrolyte should have an appropriate low conductivity, and the applied potential should be in the transient or passive region of the polarization curve recorded prior to electropolishing. It could be shown that an optimized electropolishing process improved the surface of AZ31 by providing a bright and mirror-like surface and a lower roughness compared to a mechanically ground surface.

中文翻译：

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通过调整适当的电解抛光参数获得镁合金 AZ31 的高质量表面


镁合金 AZ31 是一种轻质材料，具有良好的机械稳定性，用于各种工程应用。尽管它的局部腐蚀倾向是其使用的限制因素。电解抛光是一种广泛使用的工艺，用于改善金属的表面粗糙度和腐蚀行为。然而，缺乏关于镁及其合金的电解抛光的知识。在本研究中，开发了一种 AZ31 的最佳电解抛光工艺，通过改变电解质浓度和施加电位来改善表面性能。电解质成分是磷酸、乙醇和去离子水的混合物。根据测得的电流密度电位曲线选择施加的电位。因此，进行高达 18 As 的电荷的电解抛光。实验结果表明，电解抛光过程应在低电流密度下进行，以避免气泡逸出和表面缺陷。因此，电解液的浓度应具有适当的低电导率，并且施加的电位应位于电解抛光前记录的极化曲线的瞬态或无源区域。可以证明，与机械研磨的表面相比，优化的电解抛光工艺通过提供明亮的镜面状表面和较低的粗糙度来改善 AZ31 的表面。