Electrochemical corrosion tests were performed on samples of horizontally solidified Al7Si0.3Mg (wt%) alloy. The investigated solidification and corrosion parameters were growth and cooling rates (V_L and T_R, respectively), secondary dendritic spacing (λ₂), corrosion potential, and corrosion current (E_CORR and i_CORR, respectively). Optical and scanning electron microscopy analysis were carried out on the samples, and typical solidification microstructure was characterized by primary and eutectic phases (Al_α and Al_α-eutectic+ Si+ π-Al₈Mg₃FeSi₆+θ-Mg₂Si, respectively). The results depicted a higher corrosion resistance in as-cast samples with finer dendritic microstructure, that is, for higher and lower V_L/T_R and λ₂ values, respectively. A mathematical expression characterized the i_CORR variation with V_L, T_R, and λ₂. SEM/EDS element maps and point microanalysis showed a strong decreased of Mg and Fe elements within the interdendritic regions due to the corrosion of π and θ intermetallic phases. It was allowed to conclude that Si particles exhibit cathodic behavior in relation to the matrix as well as π and θ intermetallic compounds. A comparative analysis with the literature was also conducted.

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中文翻译：

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AlSiMg合金非稳态凝固与电化学腐蚀参数的相关性

对水平凝固的Al7Si0.3Mg（wt％）合金样品进行电化学腐蚀测试。所研究的凝固和腐蚀参数是生长和冷却速率（V_大号和Ť _{- [R} ，分别地），仲树突间距（λ ₂），腐蚀电位，腐蚀电流（E _CORR和我_CORR，分别地）。对样品进行了光学和扫描电子显微镜分析，典型的凝固组织由初生和共晶相（_Alα和Alα_共晶+ Si + π- Al ₈ Mg ₃ FeSi ₆）表征。+ θ -Mg ₂的Si，分别地）。结果描绘为铸态样品中更高的耐腐蚀性更精细枝晶组织，即，用于更高和更低的V_大号/ Ť _{- [R}和λ _2个分别值。数学表达式，其特征在于所述I _CORR，变异V_大号，Ť _{- [R}，λ ₂。SEM / EDS元素图和点微分析显示，由于π和θ的腐蚀，枝晶间区域中的Mg和Fe元素大量减少金属间相。可以得出结论，相对于基体以及π和θ金属间化合物，Si颗粒表现出阴极行为。还对文献进行了比较分析。

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