Crystallization Kinetics and Dielectric Properties of Fresnoite BaO-TiO_2-SiO_2 Glass-Ceramics

摘要

Nucleation and crystallization kinetics of fresnoite (Ba_2TiSi_2 Og) crystals in BaO-TiO_2-SiO_2 glasses have been explored for dielectric applications. The volume fractions crystallized at different temperatures and times were tracked by XRD analysis. The activation energy of crystallization was estimated from DTA results to be about 528 kJ/mol, which is consistent with the value obtained by XRD results. The Avrami parameter values calculated at different temperatures from DTA results were found to be between 3.2 and 3.9, indicating that the growth is three dimensional and the mechanism of growth is interface-controlled. Additionally, because of compositional similarities, the dielectric contrast between the glass (ε_r～ 15) and the resulting glass-ceramic (ε_r ～ 18) was minimal.