Utilisation of andesite in processing of electroceramic bodies

Abstract

The electrical properties (permittivity, power loss and conductivity) in the frequency range 200 Hz–1 MHz, as well as resisitvities of andesite bodies before and after annealing were investigated. The phase composition and microstructure of fired bodies were also determined. The densification of the crystalline phases developed microstructure. The electrical properties are greatly influenced by andesite content, maximum firing temperature and annealing time. The results suggested that the addition of 20 mass% of andesite to electroceramic bodies increased the density and the densification temperature before and after annealing. The increase in anorthite and cristobalite at the expense of quartz, mullite and augite phases increased electrical resisitvity. The permittivity and power loss were improved by increasing andesite content and annealing time as a result of reduction in porosity.