Effect of humidity on the dielectric constant and electrical impedance of mesoporous zirconia ceramics

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• 作者：Mouna Jabli Zouaoui^a ; Benoit Nait-Ali^a ; ^{benoit.nait-ali@unilim.fr" class="auth_mail" title="E-mail the corresponding author} ; Nicolas Glandut^b ; David S. Smith^a
• 关键词：Dielectric constant ; Electrical Impedance ; Relative humidity ; Porous materials ; Zirconia
• 刊名：Journal of the European Ceramic Society
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：36
• 期：1
• 页码：163-169
• 全文大小：1148 K

文摘

The effect of humidity on the dielectric constant and electrical impedance of porous 8 mol% yttria stabilized zirconia ceramic is examined. Samples with pore volume fractions from 33% to 55% were prepared from a fine powder by uniaxial pressing and firing. Measurements, in different relative humidities from <3% to 100%, showed a strong increase of dielectric constant with water content of the unfired and fired porous ceramics. The dielectric constant can be described with good agreement to experimental values using a 2 step model involving the Hashin-Shtrikman upper bound and Landauer’s effective medium relation, analogous to the behavior of thermal conductivity. Water is assumed to be located as a layer of variable thickness on the interior solid surfaces of the pores. A.c. impedance measurements also reveal a short circuit of insulating dielectric behavior at higher water contents, interpreted as surface conduction of protons.