几种固体氧化物/水蒸气体系的介电性质的研究

测定了p/p_0为0～0.75、频率为400 Hz～5 MHz范围内MgO、CaO、Ca(OH)_2及TiO_2/水蒸气体系的介电等温线与介电吸收曲线. 用M-W-S界面极化理论讨论了在一定条件下吸附(水)量与体系介电常数ε’的关系。观察到所研究的几种固体氧化物/水蒸气体系在介电性质方面的差异,并初步探讨了产生这些差异的原因。从而从不同角度为我们了解吸附剂的表面状态及其与水分子的相互作用提供了有益的信息。

On The Dielectric Properties of Several Solid Oxide/Water Vapour Systems

The dielectric isotherms and the dielectric absorption curves of MgO, CaO, Ca(OH)_2 and TiO_2 have been measured at frequency from 400 Hz to 5 MHz in the present of water vapour (p/p_0= 0 to 0.75). Based on the Maxwell-Wagner-Sillars' theory, the general relation between adsorption and dielectric constant of these systems has been discussed. The differences in dielectric properties were observed for these solid oxides mentioned above. In addition, X-ray analysis showed that after adsorption of water vapour, the calcium oxide changed into crystallite calcium hydroxide. However, the dielectric properties of this sort of calcium hydroxide are different from general Ca(OH)_2/H_2O system. The results were explained preliminarily. It is concluded that from the studies of dielectric properties the useful informations about surface state of adsorbents and interactions between adsorbent and adsorbate can be obtained.