Low-density magnesium (Mg) alloys are excellent engineering materials, and can significantly reduce energy consumption by replacing existing steel and aluminum materials. However, Mg species are susceptible to corrosion, especially in harsh environments (high-temperature or acidic), severely limiting the range of practical applications. Here, 2D covalent organic framework (COF) is synthesized with pore diameters ranging from 1.5 to 2.9 nm to obtain ultrafast nanofluidic channels. Loaded with silver (Ag⁺) ions, 2-mercaptobenzimidazole (2-MB) inhibitors are immobilized in the COF channels through the silver bridges. Based on the strong metal-complexing capability, Ag⁺ ions precipitated with various corrosive media (Cl⁻, Br⁻, I⁻, SO₃²⁻, S²⁻, S₂O₃²⁻ SO₄²⁻, CO₃²⁻, PO₄³⁻); meanwhile, the 2-MB inhibitors are rapidly released through the nanofluidic channels, forming a passivation film as a corrosion barrier to protect the Mg substrate. After integration with commercial polyethersulfone (PES), the COF-based coating exhibits high repairing capability achieving 100% damage restoration within 7 h, outperforming all existing coatings of Mg alloys. Notably, the coating shows almost complete protection of Mg alloys after being treated in respective 473 K, acidic (pH ≈4.0), and alkaline (pH ≈10.0) environments.

中文翻译：

---

通过在自修复涂层中构建纳米流体通道，对镁合金进行响应保护，使其免受多种腐蚀介质的影响


低密度镁 （Mg） 合金是优良的工程材料，可以通过替代现有的钢和铝材料来显著降低能耗。然而，镁物质容易受到腐蚀，尤其是在恶劣环境（高温或酸性）中，严重限制了实际应用的范围。在这里，合成了孔径为 1.5 至 2.9 nm 的 2D 共价有机框架 （COF），以获得超快纳米流体通道。负载银 （Ag⁺） 离子的 2-巯基苯并咪唑 （2-MB） 抑制剂通过银桥固定在 COF 通道中。基于强大的金属络合能力，Ag⁺ 离子沉淀在各种腐蚀性介质（Cl⁻、Br⁻、I⁻、SO₃²⁻、S²⁻、S₂O₃²⁻ SO₄²⁻、CO₃²⁻、PO₄³⁻）;同时，2-MB 抑制剂通过纳米流体通道迅速释放，形成钝化膜作为腐蚀屏障以保护 Mg 衬底。在与商业聚醚砜 （PES） 集成后，基于 COF 的涂层表现出高修复能力，可在 7 小时内实现 100% 的损伤修复，优于所有现有的 Mg 合金涂层。值得注意的是，该涂层在 473 K、酸性 （pH ≈4.0） 和碱性 （pH ≈10.0） 环境中处理后，几乎完全保护了 Mg 合金。