Reliability of the estimation of uniform corrosion rate of Q235B steel under simulated marine atmospheric conditions by electrochemical noise (EN) analyses

•Atmospheric corrosion rate is quantified by electrochemical noise.•The EN measurement is modeled by Thevenin equivalent circuit model.•The correlation between EN and EIS is discussed.•EN can be used in field atmospheric corrosion monitoring. This paper aims to monitoring the atmospheric corrosion of Q235B steel by electrochemical noise (EN) technique, and both statistical parameters and frequency domain analysis are used to quantify the corrosion rate. The reliability of EN measurement was evaluated by electrochemical impedance spectroscopy (EIS). Experimental results indicate that electrolyte resistance have an impact on EN measurement but it can be discarded if it is much lower than the impedance of working electrode (WE). Theoretical predictions using Thevenin equivalent circuit model reveal that spectral noise impedance is not equal to impedance module as estimated by EIS, and a relationship between them is derived. Power spectral density (PSD) obtained from experimental data further verified the theoretical predictions.