Abstract
Experiment was carried out to investigate the effect of Ba Stearate as a reducing agent on
the magnetic and physical properties of anisotropic BaFe2-W type ferrite magnets. It was found that
the magnetic properties of BaO･8.5Fe2O3 were improved by adding 0.3 wt% of Ba Stearate, 0.5
wt% of SiO2, and 0.5 wt% of CaO together. The optimum conditions for making magnets were as
follows; chemical composition: Ba1.029Ca0.127Si0.097C0.053Fe2+
2.456Fe3+
15.392O27, semisintering
condition: 1350 °C×4.0 h in nitrogen gas atmosphere, drying condition: 180 °C×2.0 h in air,
sintering condition: 1160 °C×1.5 h in nitrogen gas atmosphere. Magnetic and physical properties of
a typical sample were Jm = 0.46 T, Jr = 0.43 T, HcJ = 182.3 kA/m, HcB = 177.2 kA/m, (BH)max =
33.8 kJ/m3, TC = 495 °C and KA = 2.65×105 J/m3 and HA = 1332 kA/m. The lattice constants of this
compound were a = 5.883×10-10 m, c = 32.92×10-10 m, and c/a = 5.596.
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics,General Materials Science
Reference6 articles.
1. F.K. Lotgering, P.H.G.M. Vromans and M.A.H. Huyberts: Permanent-Magnet Material Obtained by Sintering the Hexagonal Ferrite W=BaFe18O27, J. Appl. Phys., Vol. 51 (1980), p.5913.
2. S. Toyota: Synthesis and Magnetic Properties of SrO・2FeO・8Fe2O3 W-type Hexagonal Ferrite, J. Jpn. Soc. Powder Powder Metallurgy, Vol. 44 (1997), p.17.
3. M. Ohmura and H. Yamamoto: Effect of Co Stearate Addition on Magnetic Properties of Anisotropic SrFe2 W-Type Ferrite Magnets, IEEE Trans. Magn., Vol. 40, No3 (2004), p.1695.
4. M. Ohmura, S. Kanai, and H. Yamamoto: Effect of Ni Stearate Addition on Magnetic Properties of Anisotropic SrFe2 W-Type Ferrite Magnets, Proc. of the 9th International Conference on Ferrite, San Francisco, USA (2004), p.561.
5. H. Yamamoto, K. Manabe, and M. Ohmura: Effect of Ba Stearate addition on Magnetic properties of Sr-system W-Type Ferrite Magnets, J. Jpn. Soc. Powder Powder Metallurgy, Vol. 52 (2005), p.679.