The Effect of Bi2O3 Addition on Liquid-Liquid Phase Separation, Crystallization and Dielectric Properties of Ferroelectric Glass-Ceramics in PbO-TiO2-SiO2-B2O3 System

مهندسی متالورژی و مواد

Article 5, Volume 23, Issue 2 - Serial Number 6, November 2012   

Document Type: Original Articles

DOI: 10.22067/ma.v23i2.16999

Authors

S. mohamad Mirkazemi^* ; samira golzardi; vahak marghosian; Ali Beitollahi; faezeh Sadooghi

Abstract

In this study, an attempt has been made to study the effect of Bi2O3 addition as nucleating agent on the liquid-liquid phase separation, crystallization and dielectric properties of samples prepared by sintering and crystallization of powdered glass in PbO-TiO2-B2O3-SiO2 glass-ceramic system using DTA, XRD, SEM and LCR techniques. The results showed that the addition of Bi2O3 resulted in a quite distinct liquid-liquid phase separation, i.e. spinodal decomposition, in as-quenched glass samples with significant effects on the nucleation and crystallization process. Glass ribbons were heat treated at 630-557 C for different lengths of time. Based on the results obtained, it was shown that the addition of Bi2O3 promotes the crystallization of PbTiO3. The dielectric constant (εr) increased in all heat-treated samples with increasing time except for the sample heat treated for 5 hr for which εr, decreased. This behavior was attributed to the formation of PT-Bi2O3 solid solution. The dielectric constant and dissipation factors for the glass-ceramic samples were obtained in the ranges of 33-61 and 0.007-0.02, respectively.

Keywords

Glass-ceramic; Ferroelectric; Sintering of powdered glass; liquid-liquid phase separation; Bi2O3