Sr系W型フェライトの磁気特性に及ぼすステアリン酸Alの影響 : ハード磁性材料

概要

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An experiment was carried out to investigate the effects of an Al organic compound as a new reducing agent, and SiO_2 and CaO additives, on the magnetic and physical properties of SrFe_2-hexagonal ferrite (W-type). It was found that the magnetic properties of SrO・ 8.5Fe_2O_3 were consideraly improved by adding 0.4 wt% of Al organic compound, 0.3 wt% of SiO_2, and 0.7 wt% of CaO. The optimum conditions for making magnets and the prime properties of typical specimens, according to chemical analysis, are as follows. Composition: Sr^<2+>_<0.950> Si^<4+>_<0.084>Ca^<2+>_<0.170>Al^<3+>_<0.053>Fe^<2+>_<0.813>Fe^<3+>_<16.508>O_<27>: semisintering condition (S.S.C.): 1350℃ × 5.0 h in nitrogen gas atmosphere; drying condition (D.C.): 200 ℃ × 3.0 h in air; sintering condition (S.C.): 1180 ℃ × 1.5 h in nitrogen gas atmosphere. The magnetic and physical properties of typical specimens are as follows: J_m = 0.479 T, J_r = 0.434 T, H_<cJ> = 187.48 kA/m, H_<cB> = 173.40 kA/m, (BH)_<max> = 32.71 kJ/m^3 T_c = 488.7 ℃ H_A = 1433 kA/m, K_A = 3.20×10^5 J/m^3 and η_B = 30.7 μ_B, a = 5.886 × 10^<-10> m, c = 32.785 × 10^<-10> m, and c/a = 5.570.
社団法人日本磁気学会の論文
2002-04-01