缓蚀剂负载型LDHs复合薄膜的生长行为及防护机制研究

Layered double hydroxides (LDHs) film is a new and efficient anticorrosion coating on aluminum alloy, which is used as nanocontainers for loading and releasing inhibitors. At present, many of the key issues, such as the effects of the introduction of corrosion inhibitors on the structure and properties of LDH films, life evaluation and protection mechanism of the films, are still not resolved. These limit the widespread application of the LDH films. This research prepares inhibitor-loaded LDH composite film on aluminum alloy by using in-situ growth technology. The influences of alloy phase structure and reaction conditions on LDHs film grain orientation growth are analyzed. The growth behaviors and evolution mechanism of the inhibitor-loaded LDH composite film are studied. The loaded-release process and controlled release mechanism of the guest inhibitor anions are discussed. The research is aimed to study the anticorrosion performance and damage self-healing behavior of the composite film. Combined with its in-situ growth mechanism, the comprehensive protection mechanism of the composite film is proposed, enabling the active protection of aluminum alloy. A good scientific basis for the preparation technology engineering applications of the LDH film is established.

层状双羟基复合金属氧化物（LDHs）薄膜是一种自身能够大量装载并释放缓蚀剂的“纳米容器”薄膜，近年来成为一种新型高效的铝合金表面防护材料。目前该研究尚处于起步阶段，很多关键问题如缓蚀剂引入对铝合金表面LDHs薄膜结构及性能的影响、膜层的寿命评价及综合防护机理等仍没有解决，从而限制了LDHs薄膜的广泛应用。本项目采用原位生长技术在铝合金表面制备缓蚀剂负载型LDHs复合薄膜，分析合金相组织及反应条件对LDHs薄膜晶粒取向生长的影响规律，研究缓蚀剂负载LDHs复合薄膜的生长行为及演变机制，探讨薄膜对客体缓蚀剂阴离子的负载-释放过程及控制机制。通过研究缓蚀剂负载型LDHs复合薄膜的耐蚀性能及损伤自修复行为，提出复合薄膜的综合防护机理，从而实现对铝合金材料的主动防护和智能控制，为LDHs薄膜制备技术及工程化应用奠定理论基础。

层状双羟基复合金属氧化物（Layered Double Hydroxides，LDHs）是一种阴离子型层状结构材料，近年来LDHs材料被发现其结构可以作为缓蚀剂载体，对缓蚀剂进行负载与可控释放，同时LDHs材料可通过原位生长的方法在铝合金、镁合金表面薄膜化，成为一种能够大量装载并释放缓蚀剂的智能、高效“纳米容器”防护薄膜。目前该研究尚处于起步阶段，很多关键问题如缓蚀剂引入对铝合金表面LDHs薄膜结构及性能的影响、防护机理、性能优化等仍没有解决，从而限制了LDHs薄膜的广泛应用。本课题采用原位生长技术在铝合金表面制备缓蚀剂负载型LDHs复合薄膜，分析了Al-Cu-Mg系、Al-Mg-Si系、Al-Li系铝合金中易溶、不溶合金相对薄膜晶粒生长行为的影响；探究了二价金属阳离子、晶化温度、时间、pH值、沉淀剂等制备条件对LDHs薄膜晶粒取向生长过程的影响，得出薄膜的不同成核机理与择优取向生长机制；探究了有机、无机缓蚀剂引入对LDHs薄膜取向结构与溶解-再结晶行为的影响；从主体层板阳离子组成与有机、无机客体缓蚀剂阴离子的两个方面，探究了负载行为与释放过程的内在差异，同时研究了氯离子浓度、pH值等外在条件对层间缓蚀剂释放过程的影响，并分析了负载-释放动力学行为存在差异的机理；研究了缓蚀剂负载型LDHs复合薄膜的耐蚀性能，提出了复合薄膜防护机理，同时针对LDHs薄膜多孔结构进行了工艺参数与后处理过程优化，制备出ZnAlCe三元LDHs高致密性取向薄膜与有机硅烷和石墨烯封闭的LDHs薄膜，进一步提升了膜层的综合防护性能，并建立了防护机制；进一步开展了LDHs在铝合金微弧氧化膜层表面的生长行为及防护机制研究，提出了LDHs晶粒在MAO膜层表面缺陷处的优先生长机制及修复机理，通过缓蚀剂的引入赋予了传统被动防护膜层的主动防护性能，实现对铝合金材料的主动防护和智能控制，为LDHs薄膜制备技术及工程化应用奠定理论基础。