We have studied the effect of magnetic field (B) and rotation speed (omega) of a rotating disk electrode on the corrosion current and rest potential (open circuit potential) of Zn and Fe nitrate and dichromate solutions acidified with nitric acid and sulfuric acid, respectively. We show that the anodic area of Zn and Fe can be modulated by a magnetic field or electrode rotation speed, and we introduce a semiempirical model based on the Koutecky-Levich and Butler-Volmer equations to reconstruct the relative anodic area as a function of these variables. The driving force responsible for the magnetic field induced micro-magnetohydrodynamic convection is the Lorentz force. The corrosion currents of Zn and Fe were found to increase with rotation speed and magnetic field. Rest potential shifts as large as 60 mV for Zn and 200 mV for Fe were observed in 1 M KNO3 acidified with HNO3 to pH 0.9. The rest potential is controlled by anodic current density, whereas the corrosion current density is controlled by cathodic reaction.