Fabrication of Mono-Dispersed Ultrafine BaTiO<TEX>$_3$</TEX> Powder Using Microwave

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J. Korean Ceram. Soc. > Volume 36(4); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(4): 343.

마이크로파를 이용한 초미세 균일 분산 BaTiO$_3$ 분말 제조

김현상, 최광진¹, 이상균², 김영대², 심상준², 우경자², 김경림, 조영상²

연세대학교 화학공학과
²한국과학기술연구원 청정기술연구센터

Fabrication of Mono-Dispersed Ultrafine BaTiO$_3$ Powder Using Microwave

¹Corresponding author

ABSTRACT

microwave(2.45 GHz) was used as energy source in hydrothermal reaction to fabricate ultrafine BaTiO3 powder. Using microwave of 700 W, crytal BaTiO3 began to fom after 5 min in microwave-autoclave sys-tem. The crystallinity was not noticeably increased with increasing longer reaction time than 10 min. On the other hand in microwave-reflux system crytal BaTiO3 began to form after 15min and the crystallinity was not noticeably increased with increasing longer reaction time than 1hr,. In either case particle size dis-tribution was considerably uniform due to the effect of homogeneous heating by microwave. In addition mi-crowave heating gave an extremely small degree of particle agglomeration compared to electric heating. Av-erage sizes of as-synthesized powders were 30-60nm. Ba/Ti ratio in sol played an important role in det-ermining the particle size. It seems that excess barium forms different phases such as Ba(OH)2 which makes thin layer on the surface of BaTiO3 powder. This thin layer would inhibit the agglomeration of Ba-TiO3 powders and keep the small grain size. In microwave-autoclave system tetragonal-BaTiO3 was formed directly by the reaction of only 15 min. In the case of microwave-reflux system tetragonal-BaTiO3 was formed by driyng over 25$0^{circ}C$

Key words: barium titanate, Powder, microwave, Hydrothermal, titarium acylate