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研究了施加掺杂铁红粉的环氧涂层的Al在3.5 mass%NaCl溶液(模拟海洋环境)中的电化学阻抗谱(EIS)随浸泡时间的变化,提出了两种基于高频EIS测试数据的快速评价涂层防护性能方法:局部拟合涂层电阻法和修正的特征频率法。结果表明,虽然局部拟合所得的涂层电阻值与全谱拟合所得值有一定偏差,但它们的变化趋势吻合,且很好反映了涂层的失效过程,说明局部拟合涂层电阻的方法有望被用于涂层防护性能的监检测。此外,针对传统涂层快速评价所用的特征频率法未考虑涂层电容弥散效应的不足,提出了考虑涂层电容弥散效应时特征频率的修正方法。实验观察到,在涂层浸泡过程中涂层电容对应的n值逐渐下降,而修正值与传统特征频率值差别也越来越大,说明在涂层防护性能监检测中对传统特征频率法进行修正十分必要。
The electrochemical impedance spectroscopy (EIS) changes with immersion time in 3.5 mass% NaCl solution (simulated marine environment) with epoxy coating doped with iron-red powder were studied. Two high-frequency EIS test data Rapid Evaluation of Coating Protective Properties Methods: Topically Fitted Coating Resistance Method and Modified Characteristic Frequency Method. The results show that although the values of partial resistance of the coating obtained by the local fitting have a certain deviation from the values obtained from the full spectrum fitting, their changing trend is in good agreement with each other and well reflects the failure process of the coating, indicating that the local fitting of the resistance of the coating The method is expected to be used to monitor the coating’s protective properties. In addition, the eigenfrequency method used in the rapid evaluation of traditional coatings does not consider the insufficiency of the diffusing effect of the coating capacitance, and the method of correcting the characteristic frequency when considering the diffusing effect of the coating capacitance is proposed. It is observed experimentally that the n value corresponding to the coating capacitance decreases gradually during the process of coating immersion, and the difference between the correction value and the traditional characteristic frequency value is also increasing. This shows that the traditional characteristic frequency method Correction is necessary.