Abstract
An experiment was carried out to investigate the effects of stearic acid as a new reducing agent on the magnetic and physical properties of SrFe2-W type hexagonal ferrite. It was found that the magnetic properties of SrO⋅8.5Fe2O3 were considerably improved by simultaneous addition of 0.3 wt% stearic acid, 0.3 wt%SiO2, and 0.7 wt% CaO. The optimum conditions for making magnets and some typical properties of the obtained sample are as follows. Chemical analysis composition: Sr2+0.96Si4+0.11Ca2+0.17C4+0.21Fe2+0.72Fe3+16.61O27; semi-sintering condition: 1350°C×4.0h in nitrogen gas atmosphere; drying treatment condition: 200°C×3.0h in air; sintering condition: 1170°C×1.5h in nitrogen gas atmosphere. Magnetic and physical properties are Jm=0.48 (T), Jr=0.45 (T), HcJ=169.0 (kA/m), HcB=164.7 (kA/m), (BH)max=34.6 (kJ/m3), Tc=501.5 (°C), HA=1446 (kA/m), KA=3.3 (×105 J/m3), and ηB=29.8μB, a=5.888 (×10-10m), c=32.85 (×10-10m), and c/a=5.58.
