수열 합성 공정 조건이 티탄산 납의 상 형성에 미치는 영향 |
김경아, 김정석, 천채일 |
호서대학교 대학원 반도체디스플레이 공학과 |
Effect of Hydrothermal Conditions on the Phase Evolution of Lead Titanate |
Kyoung-A Kim, Jeong-Seog Kim, Chae-Il Cheon |
Department of Semiconductor and Display Engineering, Hoseo University |
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ABSTRACT |
Lead titanate ($PbTiO_3$) powder was prepared from lead nitrate ($Pb(NO_3)_2$) and titania ($TiO_2$) by hydrothermal route. Phase formation process was investigated by observing the phases formed in various experimental conditions like different KOH concentration, reaction temperature and time. $PbTiO_3$ powder was fabricated when the KOH concentration was 0.8M or higher. An intermediate compound, $PbTi_{0.8}O_{2.6}$, was formed at first by a reaction between PbO and $TiO_2$ and changed into $PbTiO_3$ powder with a perovskite crystal structure. A $PbTiO_3$ phase was formed in a shorter time when a KOH concentration was increased from 0.8M to 8M because a driving force for a $PbTiO_3$ formation was increased due to an increase in a degree of supersaturation. And $TiO_2$ (rutile) and $3PbO{cdot}H_2O$ were observed at room temperature in a 0.8M KOH solution and $TiO_2$(rutile) and PbO (litharge) in a 8M KOH. A $PbTiO_3$phase was also formed in a shorter time at a higher reaction temperature as a reaction temperature influenced the rates for a dissolution and a precipitation. |
Key words:
Lead titanate, Hydrothermal synthesis, KOH concentration, Reaction temperature, Reaction time |
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