Assessing Corrosion in NdFeB Rails of a Superconducting MagLev Prototype

This study aims to evaluate the progression of the corrosion process in Neodymium-Iron-Boron (NdFeB) magnets that constitute the rails of the Superconducting Magnetic Levitation Vehicle. Periodic inspections were carried out on the tracks, including collecting corrosion product samples detached from the structure and rainwater samples, to determine the main constituents of the electrolyte to which the magnets are exposed. These rainwater samples were characterized by using ion chromatography, pH measurements, and conductivity analysis. In addition to sample collection, the inspections included temperature measurements of the metallic structure and a visual analysis of the rails. Based on the collected data, bench tests, electrochemical polarization, and immersion tests were conducted to simulate exposure conditions. The samples of NdFeB magnets subjected to immersion tests were analyzed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), revealing that the corrosion process progresses gradually, forming a uniform passivating layer after 45 days of immersion. However, this layer detaches entirely after 60 days, restarting the corrosion process and leading to a loss of solid material from the structure.