Lead-free high-temperature dielectrics with wide operational range
Lead-free high-temperature dielectrics with wide operational range
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DOI：
10.1063/1.3544481
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发表时间：
2011-02-01
影响因子：
3.2
通讯作者：
Roedel, Juergen
中科院分区：
文献类型：
--
作者：
Dittmer, Robert;Jo, Wook;Roedel, Juergen
研究了x=0.09，0.12，0.15，(1-x)(0.94Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3))-xK(0.5)Na(0.5)NbO(3)(BnT-BT-xKNN)的介电、电学和结构性能。和0.18作为工作温度远高于200℃的高温电容器的潜在候选者进行了研究，结果表明，在kNN(x=0.18)的最佳组成下，两个局部宽介电常数结合形成一个平台。这导致了高度温度不敏感的介电常数，最高可达300摄氏度，但绝对介电常数值略有下降。高温原位X射线衍射仪研究表明，介电材料具有伪立方对称性，没有明显的结构变化，这表明介电反常现象可能只是空间群轻微变化的结果。BNT-BT-0.18KNN在150℃1 kHz的频率下显示出类似于2150的介电常数，归一化介电常数epsilon/epsilon(150℃)在43-319℃之间变化不超过+/-10%。由于BNT-BT-0.18KNN具有非常好的电性能，即电阻率在10(8)欧姆的数量级，RC常数约为1 S，所研究的BNT-BT-xKNN组合物是开发高温电容器材料的良好起点。(C)2011年美国物理研究所。[DOI：10.1063/1.3544481]
The dielectric, electrical and structural properties of (1-x) (0.94Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3))-xK(0.5)Na(0.5)NbO(3) (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 degrees C. Temperature dependent dielectric permittivity (epsilon) 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 similar to 300 degrees 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 similar to 2150 at the frequency of 1 kHz at 150 degrees C with a normalized permittivity epsilon/epsilon(150 degrees C) varying no more than +/- 10% from 43 to 319 degrees C. With very good electrical properties persisting up to 300 degrees C, i.e., a resistivity on the order of magnitude of 10(8) Omega 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. (C) 2011 American Institute of Physics. [doi:10.1063/1.3544481]