It is well known that to evaluate the thermodynamic and kinetic parameters of a corrosion process, we must perform a polarization of +-100 mV around the potential abandon (OCP) from the cathodic zone (negative current density) going towards the anodic zone (positive current density). the cathodic zone corresponds to the immunity region of material. on the Logi = f (E) curve, around the OCP, the current density measured decreases (negative slope / reduction of O2) then increases (positive slope / metal dissolution process). finally, the sign of the slope indicates if the electrochemical process is cathodic or anodic. regardless of the sign of the slope, its absolute value is to be considered, it helps to have an idea about the easiness with which an electrochemical process occurs in response to a disturbance (polarization) and the kind of controle (anodic, cathodic or mixte). also to be able to make a comparison with other electrochemical processes.

Thank you very much Dear Abdi. you answer is clarified by doubt.