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Lead-free high-temperature dielectrics with wide operational range

Dittmer, Robert and Jo, Wook and Damjanovic, Dragan and Rödel, Jürgen (2011):
Lead-free high-temperature dielectrics with wide operational range.
In: Journal of Applied Physics, pp. 034107-1, 109, (3), ISSN 00218979, [Online-Edition: http://dx.doi.org/10.1063/1.3544481],
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Abstract

The dielectric, electrical and structural properties of (1–x)(0.94Bi1/2Na1/2TiO3–0.06BaTiO3)–xK0.5Na0.5NbO3 (BNT–BT–xKNN) with x = 0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 °C. Temperature dependent dielectric permittivity (ε) showed two local broad maxima that at the optimal composition of KNN (x = 0.18) are combined to form a plateau. This then results in a highly temperature-insensitive permittivity up to ∼ 300 °C at the expense of a small reduction in absolute permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT–BT–0.18KNN showed a permittivity of ∼ 2150 at the frequency of 1 kHz at 150 °C with a normalized permittivity ε/ε150 °C varying no more than ±10% from 43 to 319 °C. With very good electrical properties persisting up to 300 °C, i.e., a resistivity on the order of magnitude of 108 Ω m and the RC constant of about 1 s, the examined BNT–BT–xKNN compositions present a good starting point for the development of high-temperature capacitor materials.

Item Type: Article
Erschienen: 2011
Creators: Dittmer, Robert and Jo, Wook and Damjanovic, Dragan and Rödel, Jürgen
Title: Lead-free high-temperature dielectrics with wide operational range
Language: English
Abstract:

The dielectric, electrical and structural properties of (1–x)(0.94Bi1/2Na1/2TiO3–0.06BaTiO3)–xK0.5Na0.5NbO3 (BNT–BT–xKNN) with x = 0.09, 0.12, 0.15, and 0.18 were investigated as potential candidates for high-temperature capacitors with a working temperature far beyond 200 °C. Temperature dependent dielectric permittivity (ε) showed two local broad maxima that at the optimal composition of KNN (x = 0.18) are combined to form a plateau. This then results in a highly temperature-insensitive permittivity up to ∼ 300 °C at the expense of a small reduction in absolute permittivity values. High-temperature in situ x-ray diffraction study showed pseudocubic symmetry without obvious structural changes, which implies that the dielectric anomalies observed could only be a consequence of a slight change in space group. BNT–BT–0.18KNN showed a permittivity of ∼ 2150 at the frequency of 1 kHz at 150 °C with a normalized permittivity ε/ε150 °C varying no more than ±10% from 43 to 319 °C. With very good electrical properties persisting up to 300 °C, i.e., a resistivity on the order of magnitude of 108 Ω m and the RC constant of about 1 s, the examined BNT–BT–xKNN compositions present a good starting point for the development of high-temperature capacitor materials.

Journal or Publication Title: Journal of Applied Physics
Volume: 109
Number: 3
Uncontrolled Keywords: barium compounds, bismuth compounds, ceramics, crystal symmetry, dielectric materials, electrical resistivity, permittivity, potassium compounds, sodium compounds, space groups, X-ray diffraction
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis > Subproject A1: Manufacturing of ceramic, textured actuators with high strain
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 15 Jun 2011 08:13
Official URL: http://dx.doi.org/10.1063/1.3544481
Additional Information:

SFB 595 A1

Identification Number: doi:10.1063/1.3544481
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