EFFECT OF Al₂O₃ ADDITIONS ON THE DIELECTRIC PROPERTIES OF A PORCELAIN INSULATOR PREPARED FROM ECONOMICAL NATURAL RAW MATERIALS

Abstract

The aim of this work was to determine the effect of an Al₂O₃ addition on the dielectric properties of a porcelain insulator prepared from local Algerian raw materials. The new selected composition was 45 wt% kaolin, 30 wt% potash-feldspar and 25 wt% quartz. In order to find a relationship between the properties and the sample microstructures, the samples were analysed by SEM analysis, X-ray diffraction and Raman spectroscopy. The optimum sintering conditions gave a higher bulk density (2.50 g.cm−3). Dielectric measurements of porcelain insulator were carried out at 1 KHz from room temperature to 200 °C. The dielectric constant, loss factor, dielectric loss tangent and resistivity of the porcelain insulator sample containing 8 wt% Al₂O₃ sintered at 1160 °C for 2 h were: 45-50, 0.14-2.48, 0.005-0.08, and 0.9- 9 x 1013 W.cm, respectively. The value of the dielectric constant was significantly high when compared to that of that of conventional porcelains, which did not exceed generally 9.

Keywords

• porcelain insulator
• al₂o₃ additions
• dielectric properties