The Preparation and Properties of Anisotropic Glass and Glass Ceramics

Abstract

The electrical properties of 3.48 PbO - 2SiO2 glass have been studied in detail using a Cole-Berbarian AC conductivity bridge. From the results of DC electrolysis experiments and AC conductivity measurements it is concluded that the charge carrier in the glass is the Pb++ ion. Optical activity has been observed in the electrolysed glass. Anisotropic electrical conductivity and resistance to chemical attack resulting from electrolysis are also observed. A study of the electric properties and devitrification behaviour of 0.97 PbO - 3.7 Na2O - 5 SiO2 glass doped with iron is described. The glass ceramic formed by devitrification of the iron doped glass is strongly magnetic and possesses a susceptibility inversely proportional to the applied magnetic field. The devitrified glass consists of sodium-metasilicate crystals bound together with a lead-silicate glassy phase. The conditions for producing an anisotropic glass-ceramic from the sodium-lead-silicate glass, with a microstructure similar to that of an aligned directionally solidified ceramic eutectic, are reported. The use of different incident radiations to increase the information available from a radial distribution function is also described.