Analysis Technique for Improving Coercivity of Nd-Fe-B Magnets and Development of Dy-free Magnet

Hiroyuki Yamamoto, Dr. Eng. Isao Kitagawa, Dr. Sc. Teruo Kohashi, Dr. Sc. Akira Sugawara, Dr. Eng. Takeshi Nishiuchi, Dr. Eng. OVERVIEW: Hitachi is working to improve the performance of the NdFe-B magnets that help make people’s way of life more energy efficient and reduce the load it places on the environment. To study the factors that govern coercivity, an important parameter of magnet performance, Hitachi used a combination of advanced measurement techniques for evaluating the magnetic properties of a magnet’s internal structure and simulation techniques for analyzing magnetization reversal behavior. This analysis found that the properties of the grain boundary phase have a strong influence on coercivity. By working on material developments that focused on the grain boundary phase, Hitachi Metals, Ltd. has commercialized the NEOMAX Low Dy Series, a new range of Nd-Fe-B magnets developed to significantly reduce the use of Dy, a rare element.