Evaluation on Protective Performance of Organic Coatings by Analyzing the Change Rate of Phase Angle at High Frequency

Abstract

Some parameters are valuable in analyzing the organic coating performance such as coating resistance, coating capacitance, charge transfer resistance, double layer capacitance, while their extraction from EIS data is usually time-taking, furthermore, there may be some errors in calculating EIS data with equivalent circuit method. In this paper an attempt is made to introduce a new parameter obtained from the change rate of phase angle of Bode at high frequency in the electrochemical impedance spectroscopy (EIS) data. The new parameter (μ) then proved to be effective when evaluating the protective performance of a kind of grey organic coating used in vehicle equipment. The results indicated that this parameter has a good agreement with the phase angle at middle frequency of 10 Hz and the phase angle at high frequency of 10k Hz, respectively. It is concluded that the parameter can be used for fast evaluation of organic coatings in practical application.