Progress and prospects of SmFeN magnets

Abstract

More than 20 years have passed since SmFeN was discovered. At that time, because of its huge anisotropy field and high Curie temperature, SmFeN was expected to become a next-generation permanent magnetic material. However, SmFeN has the drawback that it cannot be sintered. Although considerable research has been carried out, this problem has still not been overcome. Therefore, SmFeN magnets have less potential for mass commercialization than NdFeB magnets. We propose two methods that are expected to lead to the commercial use of SmFeN. One is to increase coercivity by controlling the shape of particles, consequently increasing heat resistance. The other is to form products with new magnetic patterns by examining the magnetic orientation process. Moreover, it is important to use all rare-earth elements efficiently. Thus, we consider that SmFeN should be reappraised as a magnetic material. © 2012 The Japan Institute of Metals.