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ZnO의 입도와 산소압이 고온연소합성법으로 제조된 Ni - Zn Ferrite 분말의 자기적 특성에 미치는 영향
최용(Yong Choi),조남인(Nam Ihn Cho),한유동(Y. D. Hahn) 한국자기학회 1999 韓國磁氣學會誌 Vol.9 No.2
(Ni, Zn)Fe₂O₄ powders were prepared through self-propagating high temperature synthesis reaction and the effects of initial zinc oxide powder size and oxygen pressure on the magnetic properties of the final combustion products were studied. The ferrite powders were combustion synthesized with iron, iron oxide, nickel oxide, and zinc oxide powders under various oxygen pressures of 0.5~10 atmosphere after blended in n-hexane solution for 5 minutes with a spex mill, followed by dried at 120 ℃ in vacuum for 24 hours. The maximum combustion temperature and propagating rate were about 1250 ℃ and 9.8 ㎜/sec under the tap density, which were decreased with decreasing ZnO size and oxygen pressure. The final product had porous microstructure with spinel peaks in X-ray spectra. As the ZnO particle size in the reactant powders and oxygen pressure during the combustion reaction increase, coercive force, maximum magnetization, residual magnetization, squareness ratio were changed from 13.24 Oe, 43.88 emu/g, 1.27 emu/g, 0.0034 emu/gOe, 37.8 ℃ to 11.83 Oe, 68.87 emu/g, 1.23 emu/g, 0.00280 emu/gOe, 43.9 ℃ and 7.99 Oe, 75.84 emu/g, 0.791 emu/g, 0.001937 emu/gOe, 53.8 ℃, respectively. Considering the apparent activation energy changes with oxygen pressure, the combustion reaction significantly depended on initial oxygen pressure and ZnO particle size.