Microstructure and microwave dielectric properties of Bi 12SiO 20 ceramics

Abstract

Bi 12SiO 20 ceramics were well sintered at 800°C after calcination at 700°C. A liquid phase of composition Bi 2O 3 was formed during the sintering at temperatures ≥800°C and assisted the densification of the Bi 12SiO 20 ceramics. When the sintering temperature exceeded 800°C, however, the relative density, ε r, and Q × f values of the Bi 12SiO 20 ceramics decreased, probably due to the formation of a large amount of the liquid phase. The Bi 12SiO 20 ceramics sintered at 800°C for 5.0 h exhibited excellent microwave dielectric properties with a high ε r of 43, a high Q × f of 86,802 GHz and a small τ f of -10.39 ppm/°C. © 2012 Elsevier Ltd. All rights reserved.