• Journal of the Korean Magnetics Society
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• v.13 no.1
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• pp.29-35
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• 2003

Anisotropic Sr-ferrites were prepared by the spark plasma sintering process (SPS). The Ferrite particles were oriented and densified during sintering process, and the anisotropic ferrites were manufactured at low sintering temperature and a remarkable short time processing by SPS method. It was showed that the anisotropy of ferrite particles at the specimen outer side was more higher than that at the specimen center, and it seems possible that the orientation of ferrite particles was related to DC current. Magnetic and physical properties of sintered Sr-ferrites are Br = 3.15 kG, iHc : 2.67 kOe, and density : 5.033 g/cm$^3$ when the samples were sintered for 8 minutes at 106$0^{\circ}C$.

• Polymer(Korea)
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• v.25 no.2
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• pp.240-245
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• 2001

The effect of additives on the orientation of magnetic Sr-ferrite powders has been studied during powder injection molding under applied magnetic field for fabricating multi-pole anisotropic sintered Sr-ferrite magnets. The orientation of the Sr-ferrite powders depends sensitively on the fluidity of powder-binder mixture, related to the binder additives and the injection molding temperature, and the magnetic field intensity. The orientation of Sr-ferrite powders is good for the compacts with stearic acid added in the binder system of paraffin wax/carnauba wax/HDPE, but it is poor for the compacts with silane coupling agent added. The orientation of Sr-ferrites higher than 80% is achieved at the following useful conditions; apparent viscosity lower than 2500 poise in 1000 sec$^{-1}$ shear rate and applied magnetic field higher than 4 kOe.