Effect of Ba Strate Addition on Magnetic Properties of Ba-System W-Type Ferrite Magnets
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.
Duk Yong Yoon, Suk-Joong L. Kang, Kwang Yong Eun and Yong-Seog Kim
H. Yamamoto et al., "Effect of Ba Strate Addition on Magnetic Properties of Ba-System W-Type Ferrite Magnets ", Materials Science Forum, Vols. 534-536, pp. 1305-1308, 2007