Electrochemical impedance spectroscopy and electrochemical noise measurements as tools to evaluate corrosion inhibition of azole compounds on stainless steel in acidic media

•Introducing benzothiazole as corrosion inhibitor for stainless steel.•Electrochemical assessing inhibition behavior of benzotriazole and benzothiazole.•Electrochemical noise analysis of effectiveness of the inhibitors in 1M HCl.•Finding correlation between EIS and Electrochemical noise data.•Proposing appropriate p value to remove the DC trend from noise data. The corrosion inhibition function of two azole derivatives namely benzotriazole (BTR) and benzothiazole (BNS) on stainless steel in 1M HCl was investigated using electrochemical techniques and SEM surface analysis as well. In consistency with the data obtained from EIS and polarization curves, electrochemical current noise transient analysis, noise resistance and characteristic charge from shot noise theory indicated effectiveness of the inhibitors. The corrosion damage mitigation was also confirmed through SEM in the presence of BNS. To remove the DC trend from noise data, the appropriate p value was proposed based on the correlation with polarization and EIS data.