Devitrification kinetics and mechanism of K2O-CaO-SrO-BaO-B2O3-SiO2 glass-ceramic

The devitrification kinetics and mechanism of a low-dielectric, low-tempera ture, cofirable K2O-CaO-SrO-BaO-B2O3-SiO2 glass-ceramic have been investiga ted. Crystalline phases including cristobalite (SiO2) and pseudowollastonit e ((Ca,Ba,Sr)-SiO2) are formed during firing, Activation energy analysis sh ows that the nucleation of the crystalline phases is controlled by phase se paration of the glass. The crystallization kinetics of both cristobalite an d pseudowollastonite obey Avrami-like behavior, and the results show an app arent activation energy close to that of the diffusion of alkaline and alka li ions in the glass, suggesting that diffusion is rate limiting. The above conclusion is further supported by analysis of measured growth rates.