Abstract: Corrosion of the TiO₂ coatings which were exposed to seawater for different time periods were measured with electrochemical impedance spectroscopy（EIS），and their microstructures were investigated with SEM in order to study the corrosion failure process.The results were that the polarization resistance of the TiO₂ coatings (a measure of corrosion prevention)dropped sharply at first，and slightly increased to a stable value due to blocking of corrosion product and filths.An appropriate equivalent circuit was established to analyze the EIS，and the change of the parameters of elements in the equivalent circuit were tested in order to analyze the failure mechanism of TiO₂ coatings.

摘要： 运用电化学阻抗测试技术对不同腐蚀时间的涂层进行测试，参照等离子喷涂制备的TiO₂涂层的形貌结构特点，分析TiO₂涂层在海水介质中的腐蚀失效过程.研究表明：涂层的极化电阻在浸泡初期降低较快，后因腐蚀产物和污损物阻塞腐蚀通道，极化电阻又有所上升，趋于稳定.建立合适的等效电路分析涂层腐蚀的阻抗谱，考察各元件参数的变化，进一步分析涂层腐蚀的规律.