Effects of the magnetic field on the corrosion dissolution of the 304 SS│FeCl3 system

The effects of the magnetic field (MF, 450 mT) on the corrosion dissolution of the 304 stainless steel (304 SS) in FeCl3 solution have been studied. The dynamic processes at the electrode│electrolyte interface have been observed by using the in-line digital holography. Results show that the MF effects are different at different potentials because they vary with the elements in 304 SS: MF enhances the corrosion dissolution of Fe and Ni, but inhibits that of Cr. At low potentials, the low FL accelerates the corrosion dissolution of Fe, leading to the enhanced dissolution of 304 SS, as Fe is its main component. However, at high potentials, the high FL enhances the mass-transfer step to drive the aggressive ions away from the electrode│electrolyte interface, inhibiting the occurrence of pitting corrosion. Moreover, MF increases Cr% on the electrode surface as shown by the XPS results, and a relatively stable oxide film is formed rather easily on the surface of 304 SS. Thus, the corrosion dissolution of 304 SS is inhibited by MF.