Calotropis Procera plant extract as green corrosion inhibitor for 304 stainless steel in hydrochloric acid solution

The effect of Calotropis Procera (CP) extract on the corrosion inhibition of 304 stainless steel (SS) in 2 M HCl was studied using electrochemical (electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP) and electrochemical frequency modulation (EFM) and chemical weight loss (WL) methods at 25oC. The adsorption of the extract on 304 SS surface is consistent with Langmuir adsorption isotherm. The polarization plots revealed that the addition of extract shifts the cathodic and anodic branches towards lower currents. Such shifts indicate that CP extract acts as a mixed-type inhibitor. The thermodynamic parameters of activation and adsorption processes were calculated and discussed. The surface morphology of the 304 SS specimens was evaluating using different techniques.