Chemically Driven Zero Shrinkage Dielectric Ceramics

Abstract

A new approach of producing ~0% fired shrinkage of dielectric ceramics is introduced without using the known physically constraining interaction during firing. The combination of SiC and Al2O3 fillers with a typical calcium aluminoborosilicate glass demonstrated the potential of generating nearly zero shrinkage, presumably from the chemical reaction between the glass and SiC above a critical temperature. The sample with zero shrinkage, as exemplified with the composition of 25 wt% SiC, 25 wt% Al2O3, and 50 wt% glass, does not produce fully dense microstructure, but shows acceptable values of k (dielectric constant) ~7.4 and tanδ ~0.004 at 1 MHz. The achievement of the least shrinkage is found to be sensitive to the relative content of SiC and firing temperature.