Effects of Hydrothermal Conditions on the Morphology of Hematite Particles

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J. Korean Ceram. Soc. > Volume 31(2); 1994 > Article

Journal of the Korean Ceramic Society 1994;31(2): 117.

Hematite 입자형상에 미치는 수열반응조건의 영향

변태봉, 손진군

산업과학기술연구소 자성재료실

Effects of Hydrothermal Conditions on the Morphology of Hematite Particles

ABSTRACT

Hematite particles were obtained by hydrothermal reaction of ferric hydroxide in the presence of small amount of citric acid which is acted as crystal growth controller. The effects of hydrothermal reaction condition son the morphology and crystal structure of powder were investigated using X-ray, TEM and FT-IR. Ellipsoidal or rectangular hematite particles were formed in the range of pH 10.75~11.75 as initial basicity of reactants and 3$times$10-5 ~9$times$10-5 mol as citric acid content. Crystallization of hematite was inhibited in the range of pH9. 0~10.5 and above citric acid content of $1.5times$10-4 mol. Hematite particle length and aspect ratio were decreased gradually with increasing of citric acid content. Hematite particles formed at 14$0^{circ}C$ exhibited particle properties with the length of 0.7 ${mu}{textrm}{m}$ and aspect ratio of 8. Hematite particles having a good acicular-type were not obtained above 22$0^{circ}C$.