Although hydrogen evolution reaction (HER) is considered to be the main cathodic reaction of Mg corrosion, oxygen reduction reaction (ORR) has been recently confirmed to be a secondary cathodic reaction. The factors affecting ORR of magnesium (Mg) alloys are still unclear, especially in cases under thin electrolyte layers (TEL). In this work, the influence of the corrosion product films on the cathodic reactions of Mg alloys under TEL and in a bulk solution was investigated. ORR does not influence the hydrogen evolution rates in the corrosion of Mg alloys. Therefore, with the existence of oxygen, corrosion rates of Mg alloys measured by hydrogen evolution tests are not accurate under TEL. And weight loss test is a more accurate method to evaluate Mg corrosion rates under TEL. ORR was confirmed to participate in the corrosion of Mg–4Nd–0.4Zr, Mg–4Nd and Mg–0.4Zr alloys under TEL. In 100-μm TEL, the highest contribution of ORR in cathodic reactions for the corrosion of Mg–4Nd–0.4Zr, Mg–4Nd and Mg–0.4Zr alloys are 28.6%, 39.1%, and 35.8%, respectively. The more protective film on Mg–4Nd–0.4Zr alloy provides a stronger inhibition effect against the diffusion of oxygen, leading to decreased ORR contribution in cathodic reactions. In addition, it is suggested that the preparation of Mg alloys with protective corrosion product films can inhibit the corrosion induced by ORR in the atmosphere. This work emphasizes the effects of corrosion product films on ORR in Mg corrosion, especially under TEL.

中文翻译：

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揭示腐蚀产物与氧还原对薄电解质层下 Mg–4Nd–0.4Zr 合金腐蚀的相互作用


虽然析氢反应 （HER） 被认为是 Mg 腐蚀的主要阴极反应，但氧还原反应 （ORR） 最近已被证实是次级阴极反应。影响镁 （Mg） 合金 ORR 的因素尚不清楚，尤其是在薄电解质层 （TEL） 下的情况下。在本工作中，研究了腐蚀产物膜对 Mg 合金在 TEL 和本体溶液中的阴极反应的影响。ORR 不会影响 Mg 合金腐蚀中的析氢速率。因此，在氧气存在的情况下，通过析氢试验测得的 Mg 合金的腐蚀速率在 TEL 下并不准确。失重试验是评价 TEL 下 Mg 腐蚀速率的更准确方法。证实 ORR 参与了 TEL 下 Mg-4Nd-0.4Zr、Mg-4Nd 和 Mg-0.4Zr 合金的腐蚀。在 100 μm TEL 中，ORR 在阴极反应中对 Mg-4Nd-0.4Zr、Mg-4Nd 和 Mg-0.4Zr 合金腐蚀的最大贡献分别为 28.6%、39.1% 和 35.8%。Mg-4Nd-0.4Zr 合金上更多的保护膜对氧的扩散提供了更强的抑制作用，从而降低了阴极反应中的 ORR 贡献。此外，建议制备具有保护性腐蚀产物膜的 Mg 合金可以抑制大气中 ORR 诱导的腐蚀。这项工作强调了腐蚀产物膜对 Mg 腐蚀中 ORR 的影响，尤其是在 TEL 下。