| 초록 |
Barium titanate (BaTiO3) has been well-known as a dielectric material. BaTiO3 powdersare produced by use of solid-state and liquid-phase reactions. The hydrothermal method inthe category of liquid-phase reactions has features of producing extremely fine particles withhigh crystallinity, high purity and narrow size distribution. In that method, an aqueousBa(OH)2 solution with suspended TiO2 fine particles is treated hydrothermally, and bariumtitanate is formed through dissolution of TiO2 followed by deposition, i.e.,dissolution-deposition scheme. The dissolution rate of titania may greatly depend on whethertitania is amorphous or crystalline. Except for the kind of raw material, the relation of theparticle size to operating conditions should be investigated systematically. Furthermore, acorrelation of the specific dielectric constant of the sintered disk of barium titanate particleswith the size of the composing particle should be searched for. In this paper presented at the session of powder technology division of ’97 KIChE SpringMeeting, thus, the size control in the hydrothermal synthesis of barium ferrite and bariumtitanate fine particles to exhibit the intrinsic functions of the particles will be examined. Incase of the synthesis of barium ferrite ultrafine particles, correlations of magnetic propertiessuch as coercivity and saturation magnetization with the crystallinity of the particle wassearched for. In the case of the synthesis of barium titanate ultrafine particles, the specificdielectric constant of the sintered disk was correlated with the size of the composingparticles.
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