涂层钢在海洋多相边界及多场耦合作用下的修复机制研究

Life of coated steel reduces quickly, for easily damaged in ocean tidal range zone and splash zone, which is worst natural corrosion environment. And the conventional repairing way cannot protect it well real-time and continuously. The purpose of the project is to understand the mechanism of electro wetting and repairing in the dry and wet alternate area, induce the current of cathodic protection, generally used underwater and accomplish security protection in real time and continuously. .In order to effectively protect and restore, the field observation in sea water test site in Qingdao and micro-observation will be used, such as SEM, EDS, XRD and XPS, to understand the influence of the loose rust layer on the micro environment, electric field, chemical field and electric double layer structure of coated steel surface on the tidal range zone and splash zone. The large-scale simulated experiments, electrochemical determination (CV, EIS), micro-observation and the finite element numerical calculation will be used, to construct the physical model of cathodic protection in complex surrounding, to understand the influence law of cathodic polarization on micro environment, electric distribution, chemical reaction and electric double layer structure of coated steel surface, to understand the repairing mechanism of the sacrificial anode cathodic polarization, the impressed current cathodic polarization and pulse cathodic polarization for corroded coated in wet-dry alternated range. Taking advantage of electro capillarity inducing seawater to improve micro environment on the surface of coated steel, to understand the coupling function mechanism of controlled the flow field and electric field，to restrict corrosion of coated steel..To understand the material transfer mechanism on the surface of coated steel by controlled electric field, and to realize the function repair of the damaged coating through controlling the flowing field and electric field, it has not only important theoretical significance for anti-corrosion mechanism, but also has important application value in this area for metal structure.

海洋潮差区、飞溅带是最恶劣的自然腐蚀环境，涂层钢在该区域很容易破损，寿命迅速降低。本课题拟弄清该区域的电湿润和修复机理，将水下普遍采用的阴极保护方法引入该区域，以期做到实时、不间断防护。.为了解决有效防护及修复，拟采取海水试验场现场观测与微观测试，研究潮差区、飞溅带涂层钢表面锈层组成、结构与双电层结构特征；采取大尺度模拟实验、电化学与微观测试和有限元数值计算，建立复杂环境阴极极化的物理模型，研究牺牲阳极阴极极化、外加电流阴极极化和脉冲阴极极化对干湿交替区涂层钢界面微观环境、电场、化学场及双电层结构的影响规律及修复机制；利用电毛细现象诱导海水改善微环境，揭示控制流场与电场的耦合作用从而抑制腐蚀的机制。.揭示界面微观结构中电场作用下的物质传输机理，通过控制相应流场和电场，实现破损涂层的功能修复，不仅对了解该领域涂层钢防护机制具有重要的理论意义，也对该区域金属构件的防护更有重大的经济价值。

针对海洋潮差区、飞溅带这种最恶劣的自然腐蚀环境中，涂层钢容易破损，寿命迅速降低的难题，本课题研究了海洋用钢在该区域的腐蚀、产物特征，双电层结构以及不同电场在界面的作用，将水下普遍采用的阴极保护方法引入该区域，改变电场更好地解决干湿交替区的防护，以期做到实时、不间断防护。. 本课题设计了模拟海洋干湿交替环境腐蚀与阴极保护的模拟装置，设计制造了多通道数据采集系统；研究不同干湿周期，即不同高度海洋用钢的腐蚀过程，研究涂层钢表面锈层组成、结构与双电层结构特征，重点研究腐蚀产物及其对物理、化学流场的影响；通过大尺度模拟实验、电化学与微观测试和有限元数值计算，建立复杂环境阴极极化的物理模型；通过反演，改变流场，研究直流阴极极化对干湿交替环境涂层钢、裸钢的保护及技术方法；优化脉冲阴极极化参数，研究其对干湿交替区涂层钢界面微观环境、电场、化学场及双电层结构的影响规律及修复机制，揭示控制流场与电场的耦合作用从而抑制腐蚀的机制；将优化后的方法及参数，用于干湿交替环境裸钢以及涂层钢的长期保护，对照获得优化的技术条件；用脉冲阴极保护解决破损涂层造成的屏蔽危害，基本弄清楚电场、化学场和流体之间的相互作用。. 本课题揭示了钢与海水/湿空气以及钢与锈层界面微观结构中电场作用下的物质传输机理；通过控制相应流场和电场，实现了破损涂层的功能修复；弄清楚了直流和脉冲阴极极化对涂层钢的防护机制，也对海洋干湿交替环境金属构件的防护提出了可行的、合理的且具有操作性的技术方法，具有广阔的应用前景和经济价值。.