等方性Ca系フェライト磁石の諸性質

抄録

Many reports have been issued about ferrite permanent magnets as well as their magnetism. limiting in Ba and Sr system ferrites.
The present experiment has been carried out to investigate the optimum condition for preparing isotropic Ca ferrite magnets having the best magnetic and physical properties. Compositions were chosen according to the fomula (CaO⋅nFe₂O₃)_100-x(La₂O₃)_x and (CaO_1-ySrO_y⋅6Fe₂O₃)₉₇ (La₂O₃)₃, where x was varied between 0 and 4.0, n was varied between 5.5 and 6.25, and y was varied between 0 and 1.0.
The results are as follows; 1) The best magnetic properties of (CaO⋅nFe₂O₃)_100-x(La₂O₃)_x compounds were obtained in n=6 and x=3.2) To obtain magnets having (BH)_max more than 1.0 MG⋅e, semi-sintering at the temperature above 1200°C is required. 3) Curie temperature of (CaO⋅6Fe₂O₃)_100-x(La₂O₃)_x compounds increases with the increase of x value. 4) The magnetic properties of (CaO_1-ySrO_y⋅6Fe₂O₃)₉₇(La₂O₃)₃ magnet are improved by substitution of SrO for CaO.