염을 이용한 Sr 페라이트의 분말합성과 그의 자성특성 |
김정식, 김시동 |
서울시립대학교 신소재공학과 |
Synthesis of Sr-Ferrite by a Molten Salt Flux and Its Magnetic Properties |
Jung-Sik Kim, Si-Dong Kim |
Department of Materials Science and Engineering, The Univerity of Seoul |
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ABSTRACT |
In this study we prepared the Sr-ferrite powders and magnet by a molten salt method using the (NaCl+KCl) salt mixture. Starting materials of $Fe_{2}$$O_{3}$ and Sr$Co_{3}$ were mixed as the molar ratio of 5.70:1, and 0.08 mol$ % $ $Al_{2}$$O_{3}$, 0.10 mo1$ % $ Si$O_{2}$ and 0.12 mo1$ % $ CaO were added as additives. Sr-ferrite powders synthesized at the reaction temperatures of 800$∼$1200$ ^{circ}C $ showed the typical M-type hexagonal ferrite phase, and hexagonal plate-like morphology with uniform distribution of 1$∼$3 $mu$m particle size. The bulk density of the sintered Sr-ferrite magnet prepared with powders by the molten salt method showed the maximum density of 4.82 g/$cm^{3}$ at the sintering temperature of 1200$^{circ}C $. The maxima of remanent flux density (Br, 45 emu/g) and coercive force (iHc, 3.75 kOe) occurred at the sintering temperatures of 1150$ ^{circ}C$ and 1200$^{circ}C $. |
Key words:
Ferrite, Permanent magnet, Magnetic properties, Ceramic processing |
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