Non-monotonic influence of a magnetic field on the electrochemical behavior of Fe78Si9B13 glassy alloy in NaOH and NaCl solutions

Abstract

Abstract The corrosion behavior and microstructure of Fe78Si9B13 glassy alloy in NaOH and NaCl solutions under a 0.02-T magnetic field were investigated through electrochemical testing and scanning electron microscopy (SEM). The current-density prepeak (PP) in the anodic polarization curves in low-concentration NaOH solutions (classified as type I) tends to disappear when the NaOH concentration is increased to 0.4 mol/L and the magnetic field is applied. Under the magnetic field, the height of the second current-density peak is increased in low-concentration NaOH solutions (type I) but decreased in high-concentration NaOH solutions (type II). The non-monotonic effect of the magnetic field was similarly observed in the case of polarization curves of samples measured in NaCl solutions. Ring-like corroded patterns and round pits are easily formed under the magnetic field in NaOH and NaCl solutions. These experimental results were discussed in terms of the magnetohydrodynamic (MHD) effect.