異方性ランタン系フェライト磁石の磁気特性

抄録

Experiments were carried out to investigate the effect of CaO substitution on some properties of anisotropic La ferrite magnets. It was confirmed that the substitution of CaO to La₂O₃ contributes to formation of the magnetoplumbite structure, and these La-Ca ferrites have excellent properties as a permanent magnet. Compositions were chosen according to the formula (La₂O₃)_1-x(2CaO)_x⋅nFe₂O₃, where X was varied between 0 and 1.0, and n between 12 and 6. The optimum conditions of making magnet and some properties of a typical sample are the following: chemical analysis composition La³⁺_0.501Ca²⁺_0.697 Fe²⁺_0.212Fe³⁺_11.558O₁₉, S.S.C.: 1300°C×1 h in O₂, S.C.: 1250°C×0.5h in O₂, Jm=0.45T, Jr=0.43T, H_CJ=170.0 kA/m, H_CB=167.0 kA/m, (BH)_max=35.0 kJ/m3, H_A=1544kA/m, K_A=3.47×10₅ J/m³, σs=86.6×10^-6 Wb⋅m/kg, D=5.05 Mg/m³.