Influence of a Magnetic Field on the Electrochemical Rest Potential

Abstract

The influence of an external magnetic field on the rest potential of ferromagnetic and nonferromagnetic electrodes is studied. The shift is measured as a function of magnetic field magnitude and direction, pH, electrolyte composition, solution agitation, and electrode roughness. Anodic shifts can be observed not only for ferromagnetic electrodes (iron, cobalt, nickel), but also for nonmagnetic electrodes (zinc, manganese). The essential condition to observe the shift is that the electrode should be actively corroding. An anodic shift is observed when the cathodic corrosion current is mass-transport limited. The primary mechanism for the effect is agitation of the electrolyte near the electrode surface due to Lorentz force acting on the corrosion currents directly, or via the electrokinetic effect. A smaller influence of magnetic field gradient produced by ferromagnetic electrodes is identified.