MAGNETIC-PROPERTIES OF NANOCOMPOSITE (ND,DY)(2)(FE,CO,ZR)(14)B AND ND(FE,MO)(12)N-X MATERIALS WITH AN EXCESS OF FE

Two-phase nanocomposite materials have been prepared by high-energy ba ll-milling (HEBM) Nd12.6-uDyuFe81.4-y-zCoyZrzB6 (2:14:1 phase) (u = 0, 0.75, 1.5 or 3.0; y = 0 or 11.6 and z = 0 or 0.5) or Nd12Fe75Mo13Nx(1 :12 phase), with excess Fe and then annealing. Magnetic properties of materials containing volume fractions of up to 75% oi a magnetically s oil Fe phase have been investigated and remanence enhancement observed . Optimum magnetic properties are obtained for materials with a volume traction of a magnetically soft phase of 37-40%; for (Nd,Dy)(2)(Fe,Co ,Zr)(14)B/alpha-Fe powders a remanent magnetic polarization of 1.05 T and intrinsic coercivity of 509 kA m(-1); and for Nd(Fe,Mo)(12)N-x/alp ha-Fe powders a remanent magnetic polarization of 0.85 T and intrinsic coercivity of 281 kA m(-1). For Cc-containing alloys, evidence was ob served for the redistribution of Co in the HEBM process, resulting in a magnetically soft Fe(Co) phase. The magnetic properties of isotropic Nd-2(Fe,Co,Zr)(14)B/alpha-Fe and Nd(Fe,Mo)(12)N-x/alpha-Fe type magne ts, compacted by hot pressing, are reported.