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MgO 졸로 표면개질된 PMN-PT-BT 분말의 소결 및 유전특성

Sintering of Surface-Modified PMN-PT-BT Powder with MgO Sol and Its Dielectric Properties

  • 임경란 (한국과학기술연구원 재료연구부) ;
  • 김창삼 (한국과학기술연구원 재료연구부)
  • Han, Kyoung-Ran (Division of Materials Science and Technology, Korea Institute of Science and Technology) ;
  • Kim, Chang-Sam (Division of Materials Science and Technology, Korea Institute of Science and Technology)
  • 발행 : 2004.12.01

초록

페로브스카이트 단일상의 PMN 계 복합화합물을 제조하기 위하여 일반적으로 소량의 MgO가 과잉으로 사용되며, 잉여 MgO는 주로 입내에 석출되며 소결을 저해하는 것으로 알려져 있다. 본 연구에서는 MgO 대신 $(MgCO_3)_4{\cdot}Mg(OH)_2{\cdot}5H_{2}O$을 사용하여 고상법으로 제조한 PMN-PT-BT(PBT) 전구체 분말을 $500^{\circ}C/1h$에서 열처리한 후, MgO 졸로 표면 개질하여, 과잉의 MgO가 소결 및 물성에 미치는 영향을 조사하였다. 소량의 MgO 졸($0.5{\sim}1.0wt\%$)은 $1000^{\circ}C$ 이하의 온도에서 소결을 크게 촉진시켰다. $0.5wt\%$의 졸이 사용된 PBT 분말은 $900^{\circ}C/2h$ 소결로 소결밀도 $7.62g/cm^3$, 유전율 14800, 유전손실 $1.1\%$를 나타내었으며, 이는 PBT의 $1000^{\circ}C/2h$ 소결체의 물성과 흡사하였다. 또한 MgO 졸로 첨가된 과잉의 MgO는 삼중점과 입계에 주로 석출되어 입성장을 제어함을 알 수 있었다.

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.

키워드

참고문헌

  1. S. L. Swartz and T. R. Shrout, 'Fabrication of Perovskite Lead Magnesium Niobate,' Mater. Res. Bull., 17 1245-50 (1982) https://doi.org/10.1016/0025-5408(82)90159-3
  2. T. R. Shrout and A. Halliyal, 'Preparation of Lead-Based Ferroelectric Relaxors for Capacitors,' Am. Ceram. Soc. Bull., 66 [4] 704-11 (1987)
  3. H. Park and E. S. Lee, 'Reaction Mechanism in the Formation of PMN-PT-BT Solid Solution,' J. Kor. Ceram. Soc., 31 [I2] 1443-48 (1994)
  4. C.-H. Lu and J.-I. Lee, 'Influence of Columbite $MgNb_2O_6$ on the Perovskite Formation and Microstructure of PMN Ceramics,' J. Ceram. Soc. Jpn., 103 [11] 1122-28 (1995) https://doi.org/10.2109/jcersj.103.1122
  5. O. Bouquin, M. Leieune, and J. P. Boilot, 'Formation of the Perovskite Phase in the $PbMg_{1/3}Nb_{2/3}O_3-PbTiO_3$ System,' J. Am. Ceram. Soc., 74 [5] 1152-56 (1991) https://doi.org/10.1111/j.1151-2916.1991.tb04360.x
  6. S. L. Swartz, T. R. Shrout, W. A. Schulze, and L. E. Cross, 'Dielectric Properties of Lead Magnesium Niobate Ceramics,' J. Am. Ceram. Soc., 67 [5] 311-15 (1984) https://doi.org/10.1111/j.1151-2916.1984.tb19528.x
  7. H. Wang and W. A. Schulze, 'The Role of Excess Magnesium Oxide or Lead Oxide in Determining the Microstructure and Properties of Lead Magnesium Niobate,' J. Am. Ceram. Soc., 73 [4] 825-32 (1990) https://doi.org/10.1111/j.1151-2916.1990.tb05121.x
  8. P. A. Joy and K. Sreedhar, 'Formation of Lead Magnesium Niobate Perovskite from Niobate Precursors Having Varying Magnesium Content,' J. Am. Ceram. Soc., 80 [3] 770-72 (1997) https://doi.org/10.1111/j.1151-2916.1997.tb02896.x
  9. M. Dambekalne, M. Antonova, M. Kalnberga, A. Kalvane, M. Livinsh, I. Brante, and L. Shebanovs, 'The Effect of Technological Factors on the Synthesis of Pb$(Mg_{1/3}Nb_{2/3})O_3,'$ Ferroelectrics, 285 259-64 (2003) https://doi.org/10.1080/00150190390206095
  10. M. Koyuncu and S. M. Pilgrim, 'Effects ofMgO Stoichiometry on the Dielectric and Mechanical Response of Pb$(Mg_{1/3}Nb_{2/3})O_3,'$ J. Am. Ceram. Soc., 82 [11] 3075-79 (1999) https://doi.org/10.1111/j.1151-2916.1999.tb02205.x