| 학회 |
한국재료학회 |
| 학술대회 |
2008년 봄 (05/22 ~ 05/23, 상록리조트) |
| 권호 |
14권 1호 |
| 발표분야 |
에너지환경/생체재료 |
| 제목 |
Low Temperature Sintered Gadolinia-Doped Ceria with High Electrical Conductivity via Precipitation Synthesized Nanocrystalline Powders |
| 초록 |
A simple synthetic strategy has been implemented to obtain low temperature sintered gadolina-doped ceria, Ce0.9Gd0.1O1.95, (CGO) electrolyte pellets with high density using weakly agglomerated calcined nanopowders synthesized by a homogeneous precipitation process. The precipitants used in the precipitation processes are diethylamine (DEA process), and ammonium hydroxide in neutral precipitation (NP process). The DEA process preparation condition has influenced high yield and high quality CGO crystalline nanopowders. X-ray diffraction patterns have revealed the single phase crystalline CGO of fluorite type structure, which was directly synthesized from solution by the DEA process at room temperature (RT), whereas the NP process powder crystallized upon hydrothermal treatment at elevated temperature. Transmission electron microscopy images have showed homogeneously dispersed spherical shaped particles of ~ 5 nm sizes for nanopowders calcined at 300 °C for 4 h. Dense grain morphology was recognized from the scanning electron microscopy images of the fractured surface for the sintered pellets at 1000 °C for 4 h. The high densification range ~ 96 to 99 % of the theoretical was achieved for the non-conventionally low temperature sintered pellets at 1000 °C from weakly bonded particles of CGO nanopowders calcined at 300 °C for 4 h without any sintering aid. The optimum calcination temperature proposed for dense sintering activity of weakly agglomerated nanopowders was 300 °C, where major dehydration has occurred and absence of significant crystallite growth. The electrical transport properties were studied by ac impedance measurement as a function of temperature and sintering condition. The dense CGO pellets sintered at 1000 °C for 4 h have exhibited promising high electrical conductivity and low activation energy Ea data, which are compatible with the high temperature sintered CGO pellets reported in the literature. |
| 저자 |
조승환, P. Muralidharan, 김도경
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| 소속 |
KAIST 신소재 공학과 |
| 키워드 |
sofc; dea; electrolyte; sintering
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| E-Mail |
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