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Magnetic Properties of Sr System W-Type Ferrites.

2000; Volume: 47; Issue: 7 Linguagem: Inglês

10.2497/jjspm.47.789

1880-9014

Hiroshi Yamamoto, Kazuya Maekawa,

Microstructure and Mechanical Properties of Steels

An experiment was carried out to investigate the effects of Mg-organic-compound as a new reducing agent, and that of SiO2 and CaO additives, on the magnetic and physical properties of SrFe2-W type hexagonal ferrite. It was found that the magnetic properties of SrO·9.0Fe2O3 were considerably improved by adding 0.2 wt% Mg-organic-compound, 0.3 wt% SiO2, and 0.75 wt% CaO together. The optimum conditions for making magnets and some properties of typical specimens are as follows. Chemical analysis composition: Sr2+0.94Si4+0.093Ca2+0.188Mg2+0.001Fe2+1.368 Fe3+15.812O27; semisintering conditions: 1350°C×3.0h in nitrogen gas atmosphere; drying treatment condition: 200 °C×5.0 h in air; sintering condition: 1150°C×1.5 h in nitrogen gas atmosphere. Magnetic and physical properties are Jm=0.475 (1), Jr=0.437 (1), HcJ=203.88 (kA/m), HcB=177.46 (kA/m), (BH)max =34.22 (kJ/m3), Tc=503.8 (°C), HA= 1432.40(kA/m), KA=3.40×105J/m3, and nB=31.0μB, a=5.884(×10-10m), c=32.834 (×10-10m), and c/a=5.580.