抄録
The preparation process and magnetic properties of ε'-Fe2.2C fine particles are reported. Acicular a -FeO(OH) particles were selected as starting materials for ε'-Fe2.2C particles. α-FeO(OH) particles were heated at 260°C for 3h in air to be transformed into α-Fe2O3. The α-Fe2O3 particles had the acicular shape similar to α-FeO(OH) particle shape and contained numerous micropores with a few nanometers in diameter. α-Fe particles prepared by heating α-Fe2O3 at 300°C for 4h in H2 flow were granular and 40-60 nm in diameter. The α-Fe particles were carburized in the mixing gas flow of CO and H2 in the ratio of equal volume. ε'-Fe2.2C phase was obtained at the reaction temperatures from 200°C to 240°C. Synthesized particles were identified as a single phase ε'-Fe2.2C by XRD pattern and had the size and the shape similar to α-Fe particles. The saturation magnetization of ε'-Fe2.2C fine particles was 117 emu/g, while the coercive force was 1042 Oe.
