Corrosion behavior of sintered CeNdFeB magnets in different solutions

The capability of CeNdFeB as a substitute for NdFeB is of considerable interest due to its cost effectiveness and fascinating magnetic properties. In this paper, we have systematically investigated the corrosion behavior of the sintered CeNdFeB magnets in alkaline and acidic media in order to evaluate their commercial viability. Electrochemical and immersion tests have been conducted using sintered CeNdFeB magnets with different amounts of Ce (0.0 wt%, 29.6 wt%, 44.6 wt%, 54.8 wt%) as substitution of Nd in different concentrations of sodium hydroxide (NaOH), nitric acid (HNO3), hydrochloric acid (HCl), sulfuric acid (H2SO4), and oxalic acid (H2C2O4). We have found that the sintered CeNdFeB magnets exhibit passive behavior and the corrosion rate decreases in NaOH and H2C2O4 solutions by comparison with sintered NdFeB magnets. When exposed in strong acids, the sintered CeNdFeB has comparable corrosion properties with sintered NdFeB in HNO3 solution and lower anticorrosion properties in HCl and H2SO4 solutions. (C) 2017 Elsevier B.V. All rights reserved.