镁合金表面超疏水类水滑石膜的结构演化及腐蚀损伤机理

Owing to localized corrosion and rapid corrosion rate, magnesium alloys cannot meet the demands of clinical application. In order to solve this key technical issue, hydrotalcite-like conversion coating with biosecurity and super-hydrophobic surface will be prepared to synergistically enhance corrosion resistance and biosafety of magnesium alloy implants in the project. Influence mechanism of electric field on in-situ growth process of hydrotalcite-like conversion coating with micro-nano structure will be systematically researched. The interconnectedness between micro-nano structure and super-hydrophobicity will be explored. The role of anion exchange in structure evolution and corrosion inhibition will be clarified. The law of energy transformation, thermodynamics and kinetics of super-hydrophobic surface in the service process will be discussed. The modification mechanism of super-hydrophobic hydrotalcite-like conversion coating on corrosion resistance and biocompatibility will be demonstrated. Based on the above researches, surface properties of magnesium alloy implants in the human body environment will be improved, which will offer academic and technical supports for promoting degradable magnesium alloys to clinical application.

致力于解决镁合金因局部腐蚀及腐蚀速率过快而导致快速失效、无法临床医用的关键技术难题，本项目拟将生物安全性类水滑石膜防护技术与超疏水表面改性技术相结合，协同提高镁合金植入体的耐蚀性及生物安全性。系统研究类水滑石膜原位成膜机理，揭示电场对表面微纳结构构筑的影响规律，探索微纳结构与超疏水表面之间的内在关联，澄清类水滑石层间阴离子交换作用结构演化及其缓蚀机制，探讨腐蚀损伤过程中超疏水表面物质能量转移及热力学、动力学规律，阐明类水滑石膜超疏水表面与耐蚀性、生物相容性的关联机制，改善镁合金在人体环境中服役性能，为拓展可降解生物镁合金临床医用前景提供理论与技术支持。

基于镁合金因局部腐蚀及腐蚀速率过快而导致无法临床医用的关键技术难题，本项目致力于镁合金表面生物安全性超疏水类水滑石膜的调控设计与制备基础研究。开发了镁铁、镁锰新型水类水滑石膜的原位制备技术，系统研究了处理时间、电场辅助参数对膜层性能的影响规律及膜层组织结构及成分的演变规律，利用电场能量实现了对膜层表面微纳结构的有效调控，采用肉豆蔻酸和硬脂酸对类水滑石膜进行表面修饰，探索了电场辅助沉积法制备参数对超疏水膜层结构和性能的影响规律，揭示了腐蚀过程中超疏水膜的结构演化机制，构建了膜层的腐蚀损伤模型；对超疏水膜层进行生物抗菌实验，进一步澄清超疏水性、耐腐蚀性及生物性能之间的内在联系。研究发现，电场的引入可显著提高制备效率，并制得具有典型的“微观凸起+纳米片层”的微纳分级粗糙结构；低表面能物质和微纳分级结构的协同作用是电沉积超疏水膜具有较好腐蚀耐久性和超疏水稳定性的主要原因，而低表面能物质的解吸和脱落、微纳结构的破坏导致其腐蚀失效；超疏水膜试样抗菌性能优异，膜层超疏水性越好、耐蚀性越好、试样腐蚀释放的灭菌性镁离子越少，短时间抗菌率会略低，但该试样长时间耐蚀性和抗菌性均较优异。本项目的研究内容和结果能够为生物镁合金表面低成本、高效防护层的制备提供理论和技术支持。