Study of the electric and dielectric properties of SiO2-Li2O-Nb2O5 sol-gel glass-ceramics

被引:12
作者
Graça, M. P. F.
da Silva, M. G. Ferreira
Sombra, A. S. B.
Valente, M. A.
机构
[1] Univ Aveiro, Dept Phys, FSCOSD, P-3800193 Aveiro, Portugal
[2] Univ Aveiro, Glass & Ceram Engn Dept, CICECO, P-3800193 Aveiro, Portugal
[3] Ceara Fed Univ, Dept Phys, LOCEM, BR-60455760 Fortaleza, Ceara, Brazil
关键词
crystallization; ceramics; dielectric properties; relaxation; electric modulus; ferroelectric; nano-composites; oxide glasses; alkali silicates; silicates; sol-gels (xerogels);
D O I
10.1016/j.jnoncrysol.2006.01.084
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Glass with composition 88SiO(2-6)Li(2)O-6Nb(2)O(5) (mol%) was successfully prepared by the sol-gel technique. The dried and translucent get was heat-treated at temperatures between 500 degrees C and 800 degrees C. Lithium niobate crystallites, an important ferroelectric material, were detected in the gel derived glass-ceramics heat-treated above 650 degrees C. The de electrical conductivity (sigma(dc)) temperature dependence shows two regions with different activation energies. The dielectric constant decreases with an increase in the treatment temperature. The Z'' frequency dependence shows two relaxation peaks, one at frequencies > 1 kHz and another at low frequencies. The mean value of the relaxation times shifts to higher frequencies with an increase in measurement temperature. These dielectric behavior was an R-0(R1CPE1)(R2CPE2) equivalent circuit, using a complex non-linear least squares algorithm. The electrical and dielectrical behavior, of the glass materials, shows the important role of the treatment temperature on the gel-glass structure. (c) 2006 Elsevier B.V. All rights reserved.
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页码:1501 / 1505
页数:5
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