Synthesis and dielectric properties of layered-perovskite KCa2Nan-3NbnO3n+1 ceramics

Jong Un Woo, Sang Hyo Kweon, Mir Im, Woong Hee Lee, Chong-Yun Kang, Sahn Nahm

Research output: Contribution to journalArticle

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Abstract

KCa2NaNb4O13 (4KCNNO) 1 1KCa2NaNb4O13 defined as 4KCNNO. ceramics are well-sintered at 1325°C without any secondary phase. However, K2O evaporation occurs in KCa2Na2Nb5O16 (5KCNNO) 2 2KCa2Na2Nb5O16 defined as 5KCNNO. ceramics calcined at temperatures higher than 1200°C, resulting in the formation of the KCa2Na3Nb6O19 (6KCNNO) 3 3KCa2Na3Nb6O19 defined as 6KCNNO. secondary phase. Excess-K2O was added to the 5KCNNO specimen to synthesize pure 5KCNNO ceramics by compensating for the evaporated K2O. The 5KCNNO ceramic containing 20mol% excess-K2O sintered well at 1325°C without any secondary phase. However, the 6KCNNO secondary phase also developed in specimens containing a large excess of K2O, owing to the reaction between excess-K2O and the 5KCNNO phase. Dielectric constant (e(open) r ) of the 4KCNNO ceramic is 62 with a dielectric loss (tan δ) of 0.6% at 100kHz and the 5KCNNO ceramic showed increased e(open) r of 70 with tan δ of 0.3% at 100kHz. The increase in the e(open) r value is rationalized by the inc r eased number of NbO6 octahedral layers between the K+ layers. In addition, the structural and dielectric properties of the 5KCNNO ceramic are more important than those of the 4KCNNO ceramic from the application point of view, because the ε r value of the 5KCNNO ceramic is larger than that of the 4KCNNO ceramic.

Original languageEnglish
JournalCeramics International
DOIs
Publication statusAccepted/In press - 2017

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Dielectric losses
Dielectric properties
Perovskite
Structural properties
Evaporation
Permittivity
Temperature
perovskite

Keywords

  • A. Powders: solid state reaction
  • C. Dielectric properties
  • D. Perovskite
  • Nanosheets

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Synthesis and dielectric properties of layered-perovskite KCa2Nan-3NbnO3n+1 ceramics. / Woo, Jong Un; Kweon, Sang Hyo; Im, Mir; Lee, Woong Hee; Kang, Chong-Yun; Nahm, Sahn.

In: Ceramics International, 2017.

Research output: Contribution to journalArticle

Woo, Jong Un ; Kweon, Sang Hyo ; Im, Mir ; Lee, Woong Hee ; Kang, Chong-Yun ; Nahm, Sahn. / Synthesis and dielectric properties of layered-perovskite KCa2Nan-3NbnO3n+1 ceramics. In: Ceramics International. 2017.
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title = "Synthesis and dielectric properties of layered-perovskite KCa2Nan-3NbnO3n+1 ceramics",
abstract = "KCa2NaNb4O13 (4KCNNO) 1 1KCa2NaNb4O13 defined as 4KCNNO. ceramics are well-sintered at 1325°C without any secondary phase. However, K2O evaporation occurs in KCa2Na2Nb5O16 (5KCNNO) 2 2KCa2Na2Nb5O16 defined as 5KCNNO. ceramics calcined at temperatures higher than 1200°C, resulting in the formation of the KCa2Na3Nb6O19 (6KCNNO) 3 3KCa2Na3Nb6O19 defined as 6KCNNO. secondary phase. Excess-K2O was added to the 5KCNNO specimen to synthesize pure 5KCNNO ceramics by compensating for the evaporated K2O. The 5KCNNO ceramic containing 20mol{\%} excess-K2O sintered well at 1325°C without any secondary phase. However, the 6KCNNO secondary phase also developed in specimens containing a large excess of K2O, owing to the reaction between excess-K2O and the 5KCNNO phase. Dielectric constant (e(open) r ) of the 4KCNNO ceramic is 62 with a dielectric loss (tan δ) of 0.6{\%} at 100kHz and the 5KCNNO ceramic showed increased e(open) r of 70 with tan δ of 0.3{\%} at 100kHz. The increase in the e(open) r value is rationalized by the inc r eased number of NbO6 octahedral layers between the K+ layers. In addition, the structural and dielectric properties of the 5KCNNO ceramic are more important than those of the 4KCNNO ceramic from the application point of view, because the ε r value of the 5KCNNO ceramic is larger than that of the 4KCNNO ceramic.",
keywords = "A. Powders: solid state reaction, C. Dielectric properties, D. Perovskite, Nanosheets",
author = "Woo, {Jong Un} and Kweon, {Sang Hyo} and Mir Im and Lee, {Woong Hee} and Chong-Yun Kang and Sahn Nahm",
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T1 - Synthesis and dielectric properties of layered-perovskite KCa2Nan-3NbnO3n+1 ceramics

AU - Woo, Jong Un

AU - Kweon, Sang Hyo

AU - Im, Mir

AU - Lee, Woong Hee

AU - Kang, Chong-Yun

AU - Nahm, Sahn

PY - 2017

Y1 - 2017

N2 - KCa2NaNb4O13 (4KCNNO) 1 1KCa2NaNb4O13 defined as 4KCNNO. ceramics are well-sintered at 1325°C without any secondary phase. However, K2O evaporation occurs in KCa2Na2Nb5O16 (5KCNNO) 2 2KCa2Na2Nb5O16 defined as 5KCNNO. ceramics calcined at temperatures higher than 1200°C, resulting in the formation of the KCa2Na3Nb6O19 (6KCNNO) 3 3KCa2Na3Nb6O19 defined as 6KCNNO. secondary phase. Excess-K2O was added to the 5KCNNO specimen to synthesize pure 5KCNNO ceramics by compensating for the evaporated K2O. The 5KCNNO ceramic containing 20mol% excess-K2O sintered well at 1325°C without any secondary phase. However, the 6KCNNO secondary phase also developed in specimens containing a large excess of K2O, owing to the reaction between excess-K2O and the 5KCNNO phase. Dielectric constant (e(open) r ) of the 4KCNNO ceramic is 62 with a dielectric loss (tan δ) of 0.6% at 100kHz and the 5KCNNO ceramic showed increased e(open) r of 70 with tan δ of 0.3% at 100kHz. The increase in the e(open) r value is rationalized by the inc r eased number of NbO6 octahedral layers between the K+ layers. In addition, the structural and dielectric properties of the 5KCNNO ceramic are more important than those of the 4KCNNO ceramic from the application point of view, because the ε r value of the 5KCNNO ceramic is larger than that of the 4KCNNO ceramic.

AB - KCa2NaNb4O13 (4KCNNO) 1 1KCa2NaNb4O13 defined as 4KCNNO. ceramics are well-sintered at 1325°C without any secondary phase. However, K2O evaporation occurs in KCa2Na2Nb5O16 (5KCNNO) 2 2KCa2Na2Nb5O16 defined as 5KCNNO. ceramics calcined at temperatures higher than 1200°C, resulting in the formation of the KCa2Na3Nb6O19 (6KCNNO) 3 3KCa2Na3Nb6O19 defined as 6KCNNO. secondary phase. Excess-K2O was added to the 5KCNNO specimen to synthesize pure 5KCNNO ceramics by compensating for the evaporated K2O. The 5KCNNO ceramic containing 20mol% excess-K2O sintered well at 1325°C without any secondary phase. However, the 6KCNNO secondary phase also developed in specimens containing a large excess of K2O, owing to the reaction between excess-K2O and the 5KCNNO phase. Dielectric constant (e(open) r ) of the 4KCNNO ceramic is 62 with a dielectric loss (tan δ) of 0.6% at 100kHz and the 5KCNNO ceramic showed increased e(open) r of 70 with tan δ of 0.3% at 100kHz. The increase in the e(open) r value is rationalized by the inc r eased number of NbO6 octahedral layers between the K+ layers. In addition, the structural and dielectric properties of the 5KCNNO ceramic are more important than those of the 4KCNNO ceramic from the application point of view, because the ε r value of the 5KCNNO ceramic is larger than that of the 4KCNNO ceramic.

KW - A. Powders: solid state reaction

KW - C. Dielectric properties

KW - D. Perovskite

KW - Nanosheets

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