Influence of 4ZnO-B2O3 Addition on Dielectric Properties and Microstructures of Barium Strontium Titanate

摘要

This study investigates the effect of 4ZnO-B2O3 on the sintering behavior, dielectric properties, and microstructures of Ba0.6Sr0.4TiO3 (BST) ceramics. These ceramics were sintered in air at temperatures ranging from 900 degrees C to 1080 degrees C. BST ceramics with 4ZnO-B2O3 addition can be sintered to a theoretical density higher than 95% at 1050 degrees C. A secondary phase (Ba2ZnTi5O13) is produced in the BST ceramics during 4ZnO-B2O3 addition. Compositional analysis using TEM-EDX of the BST ceramics with 3wt% 4ZnO-B2O3 revealed that the Zn ion is generally located at the triple points. This result indicates that BaO, TiO2, and ZnO form a liquid phase that acts as a secondary phase at the lower sintering temperatures. The amount of secondary phase was observed to increase as the amount of 4ZnO-B2O3 additives increased. In addition, the original Ba0.6Sr0.4TiO3 phase was shifted to the Ba0.5Sr0.5TiO3 phase by the addition of 3wt% 4ZnO-B2O3 at 1050 degrees C. The Ba0.6Sr0.4TiO3 ceramic with 2wt% 4ZnO-B2O3 sintered at 1050 degrees C in air for 2 h exhibited dielectric properties of epsilon(r) = 1883 and dissipation loss = 0.36%. Moreover, BST with 1wt% 4ZnO-B2O3 addition sintered at 1080 degrees C exhibits dielectric properties of epsilon(r) = 2330, dissipation loss = 0.29%, and bulk density >95% of theoretical density.