Korean Journal of Chemical Engineering

, Volume 21, Issue 3, pp 582–588 | Cite as

Characterization of barium hexaferrite produced by varying the reaction parameters at the mixing-points in a supercritical water crystallization process

  • Sung-Chan Nam
  • Gun-Joong Kim


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 ‡C 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 ‡C and 40–100 s in tubular 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.

Key words

Continuous Mixing Point Barium Hexaferrite Reaction Parameter 


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  1. Adschiri, T., Kanazawa, K. and Arai, K., “Rapid and Continuous Hydrothermal Crystallization of Metal Oxide Particles in Supercritical Water,”J. Amer. Cercan. Soc,75, 1019 (1992).CrossRefGoogle Scholar
  2. Adschiri, T., Kanazawa, K. and Arai, K., “Rapid and Continuous Hydrothermal Synthesis of Boehmite Particles in Subcritical and Supercritical Water,”J. Amer. Ceram. Soc,75, 2615 (1992).CrossRefGoogle Scholar
  3. Arai, K., “Science and Technology of Supercritical Fluids,” Tohoku University (1996).Google Scholar
  4. Fujiwara, T., “Barium Ferrite Media for Perpendicular Recording,”IEEE. Trans. on Magn.,5, 1480 (1985).CrossRefGoogle Scholar
  5. Hakuta, Y, Adschiri, T., Suzuki, T., Chida, T., Seino, K. and Arai, K., “Flow Method for Rapidly Producing Barium Hexaferrite Particles in Supercritical Water,”J. Amer. Ceram. Soc,81, 2461 (1998).CrossRefGoogle Scholar
  6. Hakuta, Y., Onai, S., Adschiri, T. and Arai, K., “Production of Ultrafine Ceria Particles by Hydrothermal Synthesis under Supercritical Conditions,”J. Matter. Sci. Lett.,17, 1211 (1998).CrossRefGoogle Scholar
  7. Kumazawa, H., Cho, H. M. and Sack, E., “Hydrothermal Synthesis of Barium Ferrite Fine Particles from Goethite,”J. Mater. Sci.,28, 5247 (1993).CrossRefGoogle Scholar
  8. Kumazawa, H., Maeda, Y. and Sada, E., “Further Consideration of Hydrothermal Synthesis of Barium Ferrite Fine Particles,”J. Mater. Sci. Lett.,14, 68 (1995).CrossRefGoogle Scholar
  9. Nam, S. C. and Kim, G. J., “Preparation of Ba-Ferrite Particles Using the SuperCritical Water Crystallization Method,”J. Ind. Eng. Chem.,7, 38 (2001).Google Scholar
  10. Rho, S. W., “Influence of Stoichiometry and Alkalinity on Barium Hexaferrite Formation via the Supercritical Water Crystallization Method,”Korean J. Chem. Eng.,19, 120 (2002).CrossRefGoogle Scholar
  11. Sada, E., Kumazawa, H. and Cho, H M., “Synthesis of Barium Ferrite Ultrafine Particles by a Hydrothermal Method,”Ind. Eng. Chem. Res.,30, 1319 (1991).CrossRefGoogle Scholar
  12. Wang, M. L., Shih, Z. W. and Lin, C. H., “Reaction of Μ-Fe2O3 with Ba(OH)2 under Hydrothermal Conditions,”J. Crystal Growth,139, 47 (1994).CrossRefGoogle Scholar

Copyright information

© Korean Institute of Chemical Engineering 2004

Authors and Affiliations

  1. 1.Korea Institute of Energy ResearchDaejeonKorea
  2. 2.Inha UniversityIncheonKorea

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