화학공학소재연구정보센터
학회 한국재료학회
학술대회 2005년 가을 (11/10 ~ 11/11, 한양대학교)
권호 11권 2호
발표분야 나노 및 생체재료
제목 수열합성법에 의한 나노 Ba(Mg xTa1-x)O3 분말 합성
초록 1. Introduction
Recently, Nano Ba(Mg xTa1-x)O3 (BMT) ceramics have been studied in microwave frequency electro-material field because it has the highest Q value and a middle of dielectric constant. However, it is known to be difficult to sinter. so BMT is increasing nessicerity of nanopowder. An alternative approach from the view point of improving the powder characteristics is using the solution synthesis processes such as the precipitation and the sol-gel process method. In this study, a modified hydrothermal process was utilized for preparing the BMT materials in order to obtain nano-scale and high crystallized powders.

2. Experimental procedure
The Barium nitrate(Ba(NO3)2, Magnesium nitrate hexahydrate(Mg(NO3)6H2O), Tantalum chloride(TaCl5) were used as the raw materials to prepare BMT. The sol solution of BMT was prepared by mixing the aqueous solutions of barium and magnesium nitrates with the tantalum chloride precipitates at a molar ratio of Ba : Mg : Ta = 3 : 1 : 2. Then 1mol Potassium hydrate(KOH) was added into the mixed sol solution in order to adjust pH. The resulting suspension was placed in a 1000ml stainless steel pressure vessel. Reaction temperature was 170~200℃ and reaction time was 3~12h. The precipitations were washed at least five times by repeated cycles of centrifugation and redispersion in water and ethanol. The recovered powders were analyzed for phase composition using X-ray diffraction. The size, morphology and distribution of the synthesized particles was observed using transmission electron microscopy.

3. Results
BMT nanoparticles were synthesized by hydrothermal process from Barium nitrate(Ba(NO3)2), Magnesium nitrate hexahydrate(Mg(NO3)6H2O), Tantalum chloride(TaCl5). The completely crystallized BMT powders were obtained at the temperature of 170℃ for 6h. The average size and size distribution of the synthesized particles were 70nm and narrow, respectively.
저자 Rak Hee Kim1, Jeong Hoon Son2, Kyu Seop Park1, Dong Sik Bae2
소속 1School of Nano & adv. material. Eng., 2Changwon National Univ.
키워드 hydrothermal process; Nanoparticles; BMT
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