防腐涂层双重自修复机制及其协同作用的研究

As physical barriers, protective coatings separate metal substrates from corrosive environments, and thus inhibit the electrochemical reactions of corrosion. However, all coatings are susceptible to environmental and mechanical attacks which form defects and severely jeopardize the protectiveness. Lately, considerable research interests have been received by self-healing coatings which repair the damages by the effect of the incorporated corrosion inhibitors (autonomous healing) or by external stimuli (non-autonomous healing). Using only one of the healing mechanisms, most self-healing coatings developed to date have not shown the capability to promptly recover their long-term protectiveness against corrosion. By incorporating inhibitor-containing meltable microspheres to shape memory epoxy coatings, the proposed project describes an innovative dual-action self-healing coating system that combines the autonomous and non-autonomous self-healing mechanisms. By laboratory accelerated and outdoor exposure tests, corrosion initiation and growth at the coating damages after different healing mechanisms will be investigated making uses of macroscopic and localized electrochemistry as well as surface analytical techniques. From these results, the individual and synergistic roles of autonomous and non-autonomous healing in corrosion protection will be studied. The failure processes of self-healing coatings during long-term service environment will also be clarified. With significant scientific importance, the study will provide both theoretical and experimental support to further improve the practicality of self-healing coatings in corrosion protection.

防腐涂层通过物理屏蔽作用使金属基体与腐蚀环境隔离，阻止腐蚀电化学反应发生。但由于环境老化、外力破坏等作用，涂层不可避免的会产生破损、开裂等缺陷，防护作用显著降低。自修复涂层可通过包覆缓蚀剂以自主修复机制、或借助外界条件刺激以非自主修复机制，恢复破损涂层的防腐作用，是近年来腐蚀学科的前沿热点问题。然而，破损涂层在单一修复机制下大多难以及时、长效的恢复其防护能力。本项目将含有缓蚀剂的可熔融微球引入形状记忆环氧涂层，创新的将自主与非自主修复机制相融合，结合室内加速腐蚀试验与户外暴晒试验，利用宏微观电化学方法和表面分析技术，阐明不同修复机制对抑制涂层破损缺陷处腐蚀萌生发展各自的关键作用与协同效应，以及长期服役过程中自修复涂层的失效规律。本项目的研究成果为进一步推动自修复防腐涂层的实际应用提供了理论依据与实验基础，具有重要的科学意义。

防腐涂层通过物理屏蔽作用使金属基体与腐蚀环境隔离，阻止腐蚀电化学反应发生。但由于环境老化、外力破坏等作用，涂层不可避免的会产生破损、开裂等缺陷，防护作用显著降低。自修复涂层可通过包覆缓蚀剂以自主修复机制、或借助外界条件刺激以非自主修复机制，恢复破损涂层的防腐作用，是近年来腐蚀学科的前沿热点问题。然而，破损涂层在单一修复机制下大多难以及时、长效的恢复其防护能力。本项目创新地将自主与非自主修复机制相融合，基于pH/光热缓蚀剂响应释放、热熔胶微球熔融填充、氢键自愈，以及形状记忆修复等机制，开发了多种具有多重修复机制的涂层体系。结合室内加速腐蚀试验与户外暴晒试验，利用宏微观电化学方法和表面分析技术，阐明了不同修复机制对抑制涂层破损缺陷处腐蚀萌生发展各自的关键作用与协同效应，并证明了所制备的自修复涂层在长期服役过程中的延寿效果。本项目的研究成果为进一步推动自修复防腐涂层的实际应用提供了理论依据与实验基础，具有重要的科学意义。