Two types of permanent magnetic materials were obtained by annealing melt spun flakes : (i) materials consisting mainly of Fe3B with Nd2Fe14B as a secondary phase, and (ii) materials based on Nd2Fe14C. The methods of preparation and the resulting magnetic properties are presented

Permanent magnetic materials containing the intermetallic compound Nd2Fe14C were obtained by annealing melt-spun flakes. As quenched flakes with compositions close to the stoichiometric composition consist of α-Fe, Nd2Fe17 with some dissolved carbon, and an amorphous phase. At approximately 700 °C Nd2Fe14C is formed in a solid-state reaction. The amount of Nd2Fe14C formed, the presence of secondary phases, and the magnetic properties depend strongly on the composition. Samples with the composition Nd13.5Fe79.6C6.9 contain only a small fraction of secondary phases. The remanence and intrinsic coercive field are 0.72 T and 800 kA/m, respectively. The kinetics of the phase transformation, as well as the thermodynamics of the phase equilibria in the relevant part of the Nd-Fe-C system are discussed.

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