Sintering Behavior and Microwave Dielectric Properties of BaTi<sub>4</sub>O<sub>9</sub> Ceramics Prepared from Different Size Powders by Sol-Gel Method

Abstract

The BaTi4O9 submicron powders were synthesized by a sol-gel method, and the sintering behavior and microwave dielectric properties of BaTi4O9 ceramics prepared from powders with different particle sizes were also investigated. The particle size of powders calcined at 700 °C, 800 °C, 900 °C and 1000 °C were 8-10 nm, 70-90 nm, 100-120 nm and 140-170 nm, respectively. The 70-170 nm powders benefited the sintering process and microwave dielectric properties, whereas nanoparticles with the size of 8-10 nm damaged the sintering behavior due to the more amorphous phases and lower green density introduced by the large surface area. Sintered at 1175 °C, the BaTi4O9 ceramic prepared from 100-120 nm size nanoparticles had compact structure and exhibited good microwave dielectric properties of εr = 36.91 and Q×f = 29,833 GHz.