Magnetic Field Effects on Electrochemical Reactions Occurring at Metal/Flowing‐Electrolyte Interfaces

Abstract

A study was made to determine whether a magnetic field, such as that associated with a thermonuclear reactor, might adversely affect the corrosion behavior of metallic surfaces in contact with a flowing electrolyte. In metal/ flowing‐electrolyte systems, electrochemical reactions dependent on the metal/ electrolyte interfacial potential difference are affected by an applied magnetic field as a consequence of the Lorentz forces acting on the charged components of the flowing electrolyte. A theoretical analysis of the magnetic field effect was developed, and its validity established by experiments involving the system. Quantitative agreement between theoretical and experimental results was obtained for the electrochemical behavior of Ti in (mean flow velocity: 0–650 cm/sec) over the available range of magnetic flux density (0–2.1 Tesla). Although the experimental work employed discrete Ti electrodes set in the wall of nonconducting Pyrex glass pipe, the theory was extended to include metallic pipes, i.e., the “conducting‐wall” case, for which case the “wall‐shorting” effect was shown to be negligible. In addition to the adverse effect of a magnetic field on the “uniform” corrosion behavior of metals, the imposition of a magnetic field can also result in enhanced susceptibility to stress corrosion cracking, localized (pitting or crevice) corrosion, oxidation and reduction of solution species, and electrochemical decomposition of the electrolyte. The aforementioned processes, to name a few, are all potential dependent and, consequently, subject to the magnetic field effect.