Microstructure and properties of ZnO doped CaO–Al2O3–SiO2 ceramic for LTCC applications

Abstract

The effects of ZnO content and sintering temperature on the microstructure, bending strength, coefficient of thermal expansion and dielectric properties of Li2O–Al2O3–SiO2 glass–ceramic are presented. The prepared Li2O–Al2O3–SiO2 glass–ceramic could be used for the application of LTCC substrate. Glass powders were produced by conventional melt-quenching technique. The sintering and crystallization behavior of glass powders was explored using scanning electron microscopy, differential thermal and X-ray diffraction analyses. The crystalline phase formation in the calcination of Li2O–Al2O3–SiO2 samples has shown a major phase of Li2OAl2O37.5SiO2 and two minor phases ZrO2 and CaMgSi2O6. Increasing ZnO content at the expense of SiO2 was shown to not only promote the densification and lower the linear shrinkage, but also enhance the bending strength and the coefficient of thermal expansion of the glass–ceramic. The linear shrinkage and density of samples will decrease with the increasing sintering temperature.