Influence of adsorbed water on the dielectric response of a ceramic material

Abstract

The dielectric response of a porous ceramic has been measured in the frequency range 10^–2–10⁵ Hz and in the temperature range 290–900 K when both dry and exposed to water. These measurements have allowed the frequency dependence of the susceptibility and the temperature dependence of its magnitude and characteristic frequency to be determined. In all cases an anomalous low-frequency dispersion has been observed and substantial differences have been found between the response of the sample when dry and when containing adsorbed water. The quantitative dependence upon water content has been determined, and a tentative explanation of the behaviour is presented in terms of imperfect transport within an adsorbate system. The applicability of this model to other types of dielectrically active system which contain adsorbed species is outlined.