Impact of High-Magnitude Pulsed Currents and Magnetic Fields on Metallic Corrosion

The future naval fleet will deploy many electrical loads aboard them, many of which will be pulsed power loads that operate in a transient manner and generate high electromagnetic fields. It remains unclear to what extent high magnetic fields will affect the corrosion rate of structural and high current conducting alloys. Considering the high-pulsed currents carried within many pulsed power systems, it is of increased interest to understand what impact their deployment will have on the metallic corrosion of their own conductors as well as the structural elements around them while operational in a maritime environment. In this paper, a unique test bed has been developed on which the impact that high-pulsed currents and their induced magnetic fields have on the rate of metallic corrosion can be studied. Pulsed currents, with amplitudes just shy of 10 kA and full-width half-max lengths of roughly 4 ms, are conducted through material samples of interest immersed in a salt solution. The results from four different metallic alloys will be presented, namely, 304 stainless steel (SS), 416 SS, 1018 steel, and 8620 steel. To measure the rate of corrosion, linear polarization measurements and scanning electron microscope (SEM) imaging are used. Baseline experiments, in which the samples are only exposed to 3.5% NaCl, have also been performed to isolate the impact of high-pulsed current on the rate of corrosion. While corrosion kinetics are presented, the intent of the research is to identify if and how pulsed magnetic fields will impact material degradation, so that pulsed power engineers can prepare for it in their future system designs.