The poor corrosion resistance of magnesium (Mg) and its alloys limits their application in various fields. Micro arc oxidation (MAO) coatings can improve the corrosion resistance, but the pore defects and low surface hardness make them susceptible to wear and accelerated corrosion during usage. In this study, a ZrO₂ nanoparticles doped-MAO coating is prepared on the ZK61 Mg alloy by utilizing an MgF₂ passivation layer to prevent ablation. The ZrO₂ nanoparticles re-melt and precipitate due to local discharging, which produces evenly dispersed nanocrystals in the MAO coating. As a result, the hardness of the MAO coating with the appropriate ZrO₂ concentration increases by over 10 times, while the wear rate decreases and corrosion resistance increases. With increasing ZrO₂ concentrations, the corrosion potentials increase from −1.528 V of the bare ZK61 Mg alloy to −1.184 V, the corrosion current density decreases from 1.065 × 10^–4 A cm^–2 to 3.960 × 10^–8 A cm^–2, and the charge transfer resistance increases from 3.41 × 10² Ω cm² to 6.782 × 10⁵Ω cm². Immersion tests conducted in a salt solution for 28 d reveal minimal corrosion in contrast to severe corrosion on the untreated ZK61 Mg alloy. ZrO₂ nanoparticles improve the corrosion resistance of MAO coatings by sealing pores and secondary strengthening of the corrosion product layer.

中文翻译：

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ZrO2纳米颗粒掺杂同时提高ZK61 Mg合金微弧氧化涂层的耐磨性和耐腐蚀性


镁 （Mg） 及其合金的耐腐蚀性差限制了它们在各个领域的应用。微弧氧化 （毛） 涂层可以提高耐腐蚀性，但孔隙缺陷和低表面硬度使其在使用过程中容易受到磨损和加速腐蚀。在本研究中，利用 MgF₂ 钝化层防止烧蚀，在 ZK61 Mg 合金上制备了 ZrO₂ 纳米颗粒掺杂 毛 涂层。ZrO₂ 纳米颗粒由于局部放电而重新熔化并沉淀，从而在 毛 涂层中产生均匀分散的纳米晶体。结果，具有适当 ZrO₂ 浓度的 毛 涂层的硬度增加了 10 倍以上，同时磨损率降低，耐腐蚀性增加。随着 ZrO₂ 浓度的增加，腐蚀电位从 ZK61 Mg 裸露合金的 -1.528 V 增加到 -1.184 V，腐蚀电流密度从 1.065 × ^10-4 A ^cm-2 降低到 3.960 × ^10-8 A ^cm-2，电荷转移电阻从 3.41 ×^{10 2} Ω cm² 增加到 6.782 × 10⁵Ω cm².在盐溶液中浸泡 28 天后，与未经处理的 ZK61 Mg 合金的严重腐蚀相比，腐蚀最小。ZrO₂ 纳米颗粒通过密封孔隙和二次强化腐蚀产物层来提高 毛 涂层的耐腐蚀性。