Corrosion Behavior of NdFeB Magnets in Different Aqueous Solutions

Sintered NdFeB magnets possess excellent magnetic properties, but behave passively in alkaline and saline media and are susceptible to corrosion in acidic environments. The corrosion behavior of NdFeB magnets in industrial environments: potassium hydroxide (KOH), perchloric acid (HClO4) and sodium chloride (NaCl), was investigated by immersion and electrochemical tests. The immersion test concluded that the most corrosive electrolyte of the three studied was HClO4. Electrochemical tests showed that the NdFeB sample without magnetic order had better corrosion resistance. Metallographic microscopy and scanning electron microscopy support the obtained corrosion data. X-ray photoelectron spectroscopy indicates that the main elements on the surface of the analyzed sample (Nd, Fe, B) are in the oxidized state after corrosion.

Automated summary

Sintered NdFeB magnets have excellent magnetic properties but are susceptible to corrosion in acidic environments, while behaving passively in alkaline and saline media. The corrosion behavior of NdFeB magnets in industrial environments was studied using immersion and electrochemical tests. The results showed that the most corrosive electrolyte was HClO4, and the NdFeB sample without magnetic order exhibited better corrosion resistance. Metallographic microscopy and scanning electron microscopy supported the corrosion data, and X-ray photoelectron spectroscopy revealed the oxidation of the main elements (Nd, Fe, B) on the surface of the corroded sample.