| MgO 졸로 표면개질된 PMN-PT-BT 분말의 소결 및 유전특성 |
| 임경란, 김창삼 |
| 한국과학기술연구원 재료연구부 |
| Sintering of Surface-Modified PMN-PT-BT Powder with MgO Sol and Its Dielectric Properties |
| Kyoung-Ran Han, Chang-Sam Kim |
| Division of Materials Science and Technology, Korea Institute of Science and Technology |
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| ABSTRACT |
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It is known that small amount of MgO in excess is often added to develop pure perovskite single phase of PMN-based composite, however, extra MgO precipitates in grains and inhibits densification of PMN. In this study PMN-PT-BT (PBT) powder was prepared by a conventional mixed oxide method using $(MgCO_3)_4{cdot}Mg(OH)_2{cdot}5H_{2}O$ instead of MgO. The precursor was heated at $500^{circ}C/1h$ and its surface was modified with MgO sol. This effect was investigated in the aspects of sintering and dielectric properties. Small amount of added MgO sol ($0.5{sim}1.0wt%$) enhanced sintering substantially below $1000^{circ}C$. The PBT with $0.5wt%$ MgO sol sintered at $900^{circ}C/2h$ had density of $7.62;g/cm^3$, room temperature dielectric constant of 14800, loss of dielectric constant of $1.1%$, which were comparable to those of the PBT sintered at $1000^{circ}C/2h$. It was noticeable that the extra MgO precipitated mostly on triple points and grain boundaries and resulted in inhibition of grain growth. |
| Key words:
FMN-PT-BT, Magnesia sol, Surface-modification, Single phase perovskite, Grain growth |
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