Asymmetrical electrode effects in electrochemical noise diagnostics of organic coatings: Insights from NOCS modelling and experimentation

Electrochemical noise (ECN) measurement stands out as a robust and useful method for assessing the performance of organic coatings, providing real-time insights into their corrosion resistance and protective capabilities. A series of practical electrode arrangements expanded the application of the technique to site settings and integration of robust pseudo-reference electrodes allows a deeper understanding of the durability and longevity of organic coatings in real-world applications. The studies of coatings primarily focus on identifying defects or coating degradation originated from two or three separate areas/electrodes depending on the experimental set up. Therefore, the noise resistance, i.e. Rn value, is an amalgamation of two/three areas with different resistances that could not be distinguished individually. Herein we examine the experimental set up so-called “no connection to substrate” or NOCS as a method for separating dissimilar impedances by making multiple rotational measurements. A comparison between the more practical Ag/AgCl and the standard laboratory reference electrode, saturated Calomel electrode, has also been made.