有机涂层中离子传输行为研究

借助涂层的阴极剥离,研究了有机涂层中离子传输行为。采用一个双电解池体系,将涂层人为缺陷和完好部分隔开,通过控制两部分溶液中离子种类、浓度和pH值等,研究离子在涂层中的传输。尝试采用电化学阻抗谱技术（EIS）来表征涂层/金属界面阴极剥离程度。结果表明：K^＋能透过环氧清漆涂层到达涂层/金属界面;而Na＋很难穿透环氧清漆,只能通过涂层缺陷到达界面。溶液中水合离子直径对于离子在涂层中的扩散有着重要影响;溶液中水的活性是影响涂层起始剥离时间的主要因素。

Study of Ion Diffusion through Organic Coatings

The ion diffusion has been studied by cathodic delamination methods. A double electrochemical cell has been used to separate the solution in contact with an artificial defect and the solution in contact with the rest of the intact organic coating (epoxy polyamide coated phosphatised steel). In this way , it is possible to control the environment (ions and concentration) in the defect and around the defect. Electrochemical impedance spectra(EIS) was used to investigate delamination phenomena at the epoxy/steel interface in the two parts of the cell. The result shows that the K+ can diffuse through the epoxy coating , while Na+ can hardly diffuse through the epoxy coating. The larger the size of the hydrated cation is, the slower the diffusion rate of cations is . The water activity is one of the important influencing factor for the induction time of delamination.