Compositional optimization for nanocrystalline hard magnetic MRE-Fe-B-Zr alloys via modifying RE and B contents

To reduce the rare earth content and maintain good magnetic properties for NclFeB based alloys, the effects of RE and B contents on the micro-structure and magnetic properties of nanocrystalline MRE11-y,Fe79.5B8+yZr1.5 (MRE=Nd-0.8(DY0.5Y0.5)(0.2). Y=0-3) alloys have been investigated. Increasing B concentration leads to the appearance and increase of soft magnetic Fe3B phase and reduced grain size. With decreasing MRE and increasing B concentrations, the coercivity decreased from 1159.8 kAim for y=0 to 619.0 kAlm for y=3. The saturation magnetization and remanence increased with B content until y=2 then decreases. The B content also has effects on the exchange coupling, microstructure and thermal stability. While comparing MRE30Fe82.3B6Zr1.5 alloy with MRE11-y,Fe79.5B8+yZr1 (y=1 and 2) alloys, the alloy with 9 aL% MRE can achieve similar magnetic properties as that with 10 aL% MRE. The magnetic properties with coercivity of 792.2 kikfm, (BH)(max), of 128 kJ/m(3) and good thermal stability have been obtained for MRE9Fe79.5B10Zr1.5 alloy. (C) 2015 Elsevier B.V. All rights reserved