Enhancing corrosion resistance of Mg-Zn alloys with high strength and low cost was critical for broadening their large-scale practical applications. Here we prepared solutionized, peak- and over-aged ZK60 alloys with and without microalloying Ca (0.26 wt.%) to explore the effects of nanoscale precipitates on their corrosion behavior in detail via experimental analyses and theoretical calculations. The results suggested the peak-aged ZK60 alloy with Ca addition showed improved corrosion resistance in comparison with the alloys without Ca, owing to the contribution of Ca on the refinement of precipitates and increase in their number density. Although the precipitates and Mg matrix formed micro-galvanic couples leading to dissolution, the fine and dense precipitates could generate “in-situ pinning” effect on the corrosion products, forming a spider-web-like structure and improving the corrosion inhibition ability accordingly. The pinning effect was closely related to the size and number density of precipitates. This study provided important insight into the design and development of advanced corrosion resistant Mg alloys.

以高强度和低成本提高镁锌合金的耐腐蚀性对于扩大其大规模实际应用至关重要。在这里，我们制备了含有和不含微合金化 Ca（0.26 wt.%）的固溶、峰值和过时效 ZK60 合金，通过实验分析和理论计算详细探讨纳米级析出物对其腐蚀行为的影响。结果表明，与不含Ca的合金相比，添加Ca的峰值时效ZK60合金表现出更好的耐腐蚀性，这是由于Ca有助于细化析出物并增加其数量密度。虽然析出物与镁基体形成微电偶导致溶解，但细密的析出物能够对腐蚀产物产生“原位钉扎”效应，形成蜘蛛网状结构，从而提高缓蚀能力。钉扎效应与析出物的尺寸和数密度密切相关。这项研究为先进耐腐蚀镁合金的设计和开发提供了重要的见解。