Microstructure and magnetic properties of Nd95−Fe C5 (15⩽x⩽65) alloys

Abstract This work investigates the range of existence of the D 1 -phase in Nd 95− x Fe x C 5 (15⩽ x ⩽65) alloys. A comparative study of the microstructure of this alloy system, in the as-cast state and after annealing at 600°C, was carried out. In as-cast samples with 15⩽ x ⩽45, besides the presence of Nd grains and large needles, quite corrosive Nd-based carbides are formed. According to TMA curves, D 1 is the major magnetic phase formed in this composition range. For x >45 primary Nd 2 Fe 17 crystals, surrounded by corrosive Nd-C phases, were observed. By increasing the Fe-content the population of needle-like particles formed in the intergranular region also increases. In both as-cast and annealed samples with 15⩽ x ⩽45, the intrinsic coercivity decreases with the increase of Fe content indicating that the phase D 1 is mainly responsible for the high coercivity in these alloys.