Magnetic properties of melt-spun (Nd,Dy)2Fe14(B,C)

Abstract Hard magnetic materials based on the Nd 2 Fe 14 C, (Nd,Dy) 2 Fe 14 C and (Nd,Dy) 2 Fe 14 (B,C) phases have been prepared by vacuum annealing of melt-spun ribbons. A coercivity μ 0J H c of about 2.5 T can be obtained directly by melt-spinning Nd 13 Dy 2 Fe 77 C 6 B 2 . All as-quenched ribbons consist mainly of three phases: (Nd,Dy) 2 Fe 17 C x (2:17), (Nd,Dy) 2 Fe 14 (B,C) (2:14:1) and α-Fe. Due to short-time annealing, the 2:17 phase transforms into the 2:14:1 phase. Substitution of carbon by boron accelerates the formation of 2:14:1 phase in the as-spun ribbons. Dy substitution for Nd increases the coercivity of Nd–Fe–C based magnets. After optimization an energy product of (BH) max =76 kJ/m 3 , a remanence of B r =0.71 T, and a coercivity of μ 0J H c =2.0 T were achieved for annealed Nd 13 Dy 2 Fe 77 C 6 B 2 ribbons. Fully dense, textured (Nd,Dy) 2 Fe 14 (B,C) magnets with (BH) max of up to 137 kJ/m 3 could be produced by hot pressing coarsely ground ribbons and subsequent die-upsetting.