Sr系W型フェライトの磁気特性－第2報－

抄録

An experiment was carried out to investigate the effects of a Zn-organic-compound as a new reducing agent, and SiO₂ and CaO additives, on the magnetic and physical properties of SrFe₂-hexagonal ferrite (W type). It was found that the magnetic properties of SrO⋅9.0Fe₂O₃ were considerably improved by adding 0.1 wt% of Zn-organic-compound, 0.3 wt% of SiO₂, and 0.7 wt% of CaO together. The optimum conditions for making magnets and the prime properties of typical specimens are as follows: Based on chemical analysis: Composition: Sr²⁺_0.930Si⁴⁺_0.097 Ca²⁺_0.169Zn²⁺_0.007Fe²⁺_1.307, Fe³⁺_16.265O₂₇; semisintering conditions (S.S.C.): 1350°C×4.0h in nitrogen gas atmosphere; drying condition (D.C.): 200°C×4.0 h in air; sintering condition (S.C.): 1170°C×1.5 h in nitrogen gas atmosphere. Magnetic and physical properties are as follows: J_m=0.468(T). J_r=0.433(T), H_cJ=175(kA/m), H_cB=161(kA/m), (BH)_max=32.70(kJ/m³), T_c=500.9(°C), H_A=1401 (kA/m), K_A=3.28, and n_B=30.0μ_B, a=5.757×10^-10(m), c=33.41×10_-10(m), and c/a=5.804.