Permanent magnetic materials based on Nd₂Fe_{1 4}C prepared by melt spinning

Permanent magnetic materials containing the intermetallic compound Nd ₂Fe₁₄C 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 Nd_13.5Fe _79.6C_6.9 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.