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In relation to this article, we declare that there is no conflict of interest.
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Received September 4, 2003
Accepted December 30, 2003
articles This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Characterization of Barium Hexaferrite Produced by Varying the Reaction Parameters at the Mixing-Points in a Supercritical Water Crystallization Process

Korea Institute of Energy Research, P.O. Box 103, Yusong, Daejeon 305-600, Korea 1Inha University, 253 YongHyun-dong, Nam-Ku, Incheon 402-751, Korea
scnam@kier.re.kr
Korean Journal of Chemical Engineering, May 2004, 21(3), 582-588(7), 10.1007/BF02705491
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Abstract

Barium hexaferrite (BaFe12O19) was synthesized from a Ba(NO3)2, Fe(NO3)3 and KOH mixed solution by hydrothermal treatment of the solution using a supercritical water flow apparatus. The first step is the hydrolysis of the nitrates of barium and iron in potassium hydroxide; the pressure and temperature were adjusted in the respective range of 25-40 MPa and 100-250 ℃ in tee reactor (MP2). The second one is the dehydration of the formed hydrolytic products, under the supercritical state of the solvent in the range of 25-40 MPa, 300-450 ℃ and 40-100 s in tubular_x000D_ flow reactor (MP3). All samples of barium hexaferrite were prepared without calcination of the dehydrated products. Using this method, smaller, uniform-size and single-phase BaFe12O19 nanocrystals could be easily obtained.

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