Activation of the sintering process of a quartz electrical porcelain body

Abstract

The influence of cyclic heating of a quartz electrical porcelain body at the temperature of polymorphic transformation of α- to β-quartz (∼573°C) on structural characteristics has been studied. Based on changes in surface area and shrinkage measurements during linear heating of the samples investigated, the optimal number of thermal cycles was determined. Microstructural investigations of the sample analysed (including both industrial products and those activated by thermal cycles) have indicated the influence of Hedwall's effect on the kinetics of primary and secondary mullite formation. With cycle-induced activation a lowering of the sintering temperature needed for maturation of the system was observed. © 1990.