Composition-dependent magnetic properties of melt-spun La or/and Ce substituted nanocomposite NdFeB alloys

Aiming at high-performance low-cost NdFeB magnets, the magnetic properties and microstructure for melt spun nanocrystalline (Nd1-xMx)(10)Fe84B6 (M= La, Ce, or La0.5Ce0.5; x=0-0.7) alloys were investigated. Relatively, LaCe-substituted alloys show high values of the remanent magnetization M-r, the maximum energy product (BH)(max) and the coercivity H-c, up to 114 emu/g (1.07 T), 147 kJ/m(3) and 471 kA/m, respectively, at x=0.1. The unusual increase in coercivity for the alloys with 10% La or 10% La0.5Ce0.5 substitution is possibly attributed to the phase segregation in alloys with certain La or LaCe contents. The reduced Curie temperature and spin-reorientation temperature were obtained for La, Ce or LaCe substituted alloys. Transmission electron microscope analysis has revealed that a fine and uniform distributed grain structure leads to remanence enhancement for La0.5Ce0.5 substituted alloys. The present results indicate that partially substituting Nd by La or/and Ce cannot only effectively reduce the cost of nanocrystalline NdFeB based magnetic powders but also can maintain a relatively good combination of magnetic properties. (C) 2015 Elsevier B.V. All rights reserved.