电化学阻抗谱（EIS）在ZAHNER电化学工作站上收集。测试频率范围为105~10-2 Hz。使用三电极体系，涂层样板作工作电极，暴露面积约为10 cm2；饱和甘汞电极为参比电极，铂电极为辅助电极。电解质溶液为10% H2SO4溶液，5% NaOH溶液以及3.5% NaCl溶液。高固体份涂层和无溶剂涂层的扰动电压设为20 mV，水性涂层扰动电压设为10 mV。在室温，开路电位下进行电化学阻抗测量。

Electrochemical impedance spectroscopy (EIS) was collected on a ZAHNER electrochemical workstation. The test frequency range is 105~10-2 Hz. The three-electrode system was used, and the coated sample was used as the working electrode, and the exposed area was about 10 cm2. The saturated calomel electrode is the reference electrode and the platinum electrode is the auxiliary electrode. The electrolyte solution was 10% H2SO4 solution, 5% NaOH solution and 3.5% NaCl solution. The disturbance voltage of high solid content coating and solvent-free coating was set to 20 mV, and that of water-based coating was set to 10 mV. Electrochemical impedance measurements were performed at room temperature, open circuit potential.