The influence of alloying with Sn and Mg instead of In during casting of Al–5 wt% Zn sacrificial anodes on their microstructure and electrochemical properties was investigated. The addition levels were 0.1–1.0 wt% Sn and 0.5–2.0 wt% Mg. The different microstructures were studied, and the effect of particles distribution on the performance of the alloys as sacrificial anodes was discussed. It was observed that increasing amount of Sn distributes its particles locally on the grain boundaries which remarkably affected the electrochemical behavior of the alloys. Adding Sn up to 1.0% gradually shifted the potential of the Al–5 wt% Zn alloy toward more negative values (~ − 0.92 to − 1.1 V) and enhanced the breakdown of the oxide layer. Accordingly, the alloys containing Sn in amounts that range between 0.3 and 1.0 wt% exhibited electrochemical properties close to that of the In-containing alloy. Magnesium addition of 0.5 wt% showed remarkable grain refinement where the grain size range of the base alloy was reduced from (150–200 μm) down to (70–100 μm) due to Mg distribution on the grain boundary area. With increasing Mg wt%, grain coarsening occurred due to the segregation of Mg in the matrix which encouraged the breakdown of the passive film and hence increased the corrosion rate. However, the potential levels of the investigated Mg alloys showed more positive values compared to that of the In-containing alloy, which may hinder using this group of alloys for sacrificial anodes applications.

研究了在铸造Al-5 wt％Zn牺牲阳极时与Sn和Mg代替In合金化对其微观结构和电化学性能的影响。添加量为0.1–1.0 wt％的Sn和0.5–2.0 wt％的Mg。研究了不同的微观结构，并讨论了颗粒分布对合金作为牺牲阳极性能的影响。观察到，增加量的Sn将其颗粒局部地分布在晶界上，这显着影响了合金的电化学行为。添加最多1.0％的Sn逐渐将Al-5 wt％Zn合金的电势移向更多的负值（〜-0.92至-1.1 V），并增强了氧化层的击穿能力。因此，含Sn量在0.3和1之间的合金。0wt％的电化学性能接近含In的合金。添加0.5 wt％的镁显示出显着的晶粒细化效果，由于镁在晶界区域的分布，基础合金的晶粒尺寸范围从（150-200μm）减小到（70-100μm）。随着Mg重量％的增加，由于Mg在基体中的偏析而发生晶粒粗化，这促进了钝化膜的击穿并因此提高了腐蚀速率。但是，与含In的合金相比，所研究的Mg合金的电位水平显示出更大的正值，这可能会妨碍将这组合金用于牺牲阳极应用。5 wt％的晶粒细化效果显着，由于镁在晶界区域的分布，基础合金的晶粒尺寸范围从（150-200μm）减小到（70-100μm）。随着Mg重量％的增加，由于Mg在基体中的偏析而发生晶粒粗化，这促进了钝化膜的击穿并因此提高了腐蚀速率。但是，与含In的合金相比，所研究的Mg合金的电位水平显示出更大的正值，这可能会妨碍将这组合金用于牺牲阳极应用。5 wt％的晶粒细化效果显着，由于镁在晶界区域的分布，基础合金的晶粒尺寸范围从（150-200μm）减小到（70-100μm）。随着Mg重量％的增加，由于Mg在基体中的偏析而发生晶粒粗化，这促进了钝化膜的击穿并因此提高了腐蚀速率。但是，与含In的合金相比，所研究的Mg合金的电位水平显示出更大的正值，这可能会妨碍将这组合金用于牺牲阳极应用。