中文摘要：

应用阵列电极（WBE）联合电化学阻抗谱（EIS）技术,研究了气/液界面水线处破损涂层在3.5%（质量分数）NaCl溶液中的水线区破损涂层剥离行为。对比涂层剥离过程的腐蚀电流密度和阻抗谱分布行为,探讨了破损涂层在水线区的剥离机制。结果表明,涂层破损区和固有缺陷区均能够加速附近涂层阴极剥离过程。水线区破损涂层剥离行为特征为,破损区和固有缺陷区附近涂层首先发生阴极剥离,进而向外部涂层/金属界面扩展。此外,研究发现,破损区位于水线上方和下方时,其推动阴极剥离能力不同,即,加速水线下方涂层剥离作用弱于水线上方区域,致使水线及水线上方涂层剥离速率明显大于水线下涂层剥离速率。其原因显然与阴极剥离区溶解氧含量有关,即富氧区阴极剥离扩展速率大于乏氧区阴极剥离速率。

英文摘要：

Organic coatings on metal surface usually present inherent local defects, thus are easy to be deteriorated. The characteristic of corrosion beneath coatings with damages（i.e. the inherent or artificial ones） is that the inherent defect and the debonding defect may be coupled together to induce nonuniform corrosion of the metal substrate. Hence, the debonding process of organic coating with artificial defects nearby the waterline in 3.5%（mass fraction） Na Cl solution was studied by means of wire beam electrode（WBE） method coupled with electrochemical impedance spectroscopy（EIS） technique.Through analyzing the variations of current distribution, coating impedance, impedance spectroscopy in the disbonding process, the debonding mechanism for the damaged coating in areas nearby the waterline could be revealed. The result showed that, the cathodic disbonding was expedited in the area around the inherent defect or the artificial defect. The characteristic of disbonding process for damaged coating near waterline is that, the cathodic disbonding first happened nearby the inherent defect as well as the artificial defect, and then expanded around. Besides, the position of the artificial defect can affect the cathodic disbonding process. When the artificial defect just located on the waterline, the disbonding rate above the waterline was higher than that below the waterline. It was because that the higher the oxygen content is, the faster the disbonding rate well be.