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

Korean Journal of Chemical Engineering, Vol.21, No.3, 582-588, May, 2004

Sung-Chan Nam^†, and Gun-Joong Kim¹

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

E-mail:

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 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.

Keywords:Continuous;Mixing Point;Barium Hexaferrite;Reaction Parameter

[References]

Adschiri T, Kanazawa K, Arai K, J. Am. Ceram. Soc., 75, 1019 (1992)
Adschiri T, Kanazawa K, Arai K, J. Am. Ceram. Soc., 75, 2615 (1992)
Arai K, "Science and Technology of Supercritical Fluid," Tohoku University (1996)
Fujiwara T, IEEE Trans. Magn., 5, 1480 (1985)
Hakuta Y, Adschiri T, Suzuki T, Chida T, Seino K, Arai K, J. Am. Ceram. Soc., 81, 2461 (1998)
Hakuta Y, Onai S, Terayama H, Adschiri T, Arai K, J. Mater. Sci. Lett., 17(14), 1211 (1998)
Kumazawa H, Cho HM, Sada E, J. Mater. Sci., 28, 5247 (1993)
Tumazawa H, Maeda Y, Sada E, J. Mater. Sci. Lett., 14(1), 68 (1995)
Nam SC, Park SD, Kim GJ, J. Ind. Eng. Chem., 7(1), 38 (2001)
Rho S, Park S, Korean J. Chem. Eng., 19(1), 120 (2002)
Sada E, Kumazawa H, Cho HM, Ind. Eng. Chem. Res., 30, 1319 (1991)
Wang ML, Shih ZW, Lin CH, J. Cryst. Growth, 139, 47 (1994)

[Referenced By]

[Related Articles]

[1] Adschiri T, Kanazawa K, Arai K, J. Am. Ceram. Soc., 75, 1019 (1992)

[2] Adschiri T, Kanazawa K, Arai K, J. Am. Ceram. Soc., 75, 2615 (1992)

[3] Arai K, "Science and Technology of Supercritical Fluid," Tohoku University (1996)

[4] Fujiwara T, IEEE Trans. Magn., 5, 1480 (1985)

[5] Hakuta Y, Adschiri T, Suzuki T, Chida T, Seino K, Arai K, J. Am. Ceram. Soc., 81, 2461 (1998)

[6] Hakuta Y, Onai S, Terayama H, Adschiri T, Arai K, J. Mater. Sci. Lett., 17(14), 1211 (1998)

[7] Kumazawa H, Cho HM, Sada E, J. Mater. Sci., 28, 5247 (1993)

[8] Tumazawa H, Maeda Y, Sada E, J. Mater. Sci. Lett., 14(1), 68 (1995)

[9] Nam SC, Park SD, Kim GJ, J. Ind. Eng. Chem., 7(1), 38 (2001)

[10] Rho S, Park S, Korean J. Chem. Eng., 19(1), 120 (2002)

[11] Sada E, Kumazawa H, Cho HM, Ind. Eng. Chem. Res., 30, 1319 (1991)

[12] Wang ML, Shih ZW, Lin CH, J. Cryst. Growth, 139, 47 (1994)