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

This study investigates the effect of 4ZnO–B 2 O 3 on the sintering behavior, dielectric properties, and microstructures of Ba 0.6 Sr 0.4 TiO 3 (BST) ceramics. These ceramics were sintered in air at temperatures ranging from 900°C to 1080°C. BST ceramics with 4ZnO–B 2 O 3 addition can be sintered to a theoretical density higher than 95% at 1050°C. A secondary phase (Ba 2 ZnTi 5 O 13 ) is produced in the BST ceramics during 4ZnO–B 2 O 3 addition. Compositional analysis using TEM‐EDX of the BST ceramics with 3 wt% 4ZnO–B 2 O 3 revealed that the Zn ion is generally located at the triple points. This result indicates that BaO, TiO 2 , 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–B 2 O 3 additives increased. In addition, the original Ba 0.6 Sr 0.4 TiO 3 phase was shifted to the Ba 0.5 Sr 0.5 TiO 3 phase by the addition of 3 wt% 4ZnO–B 2 O 3 at 1050°C. The Ba 0.6 Sr 0.4 TiO 3 ceramic with 2 wt% 4ZnO–B 2 O 3 sintered at 1050°C in air for 2 h exhibited dielectric properties of ɛ r =1883 and dissipation loss=0.36%. Moreover, BST with 1 wt% 4ZnO–B 2 O 3 addition sintered at 1080°C exhibits dielectric properties of ɛ r =2330, dissipation loss=0.29%, and bulk density >95% of theoretical density.