Liquid phase effect of Bi₂O₃ additive on densification, microstructure and microwave dielectric properties of Mg₂TiO₄ ceramics

ABSTRACT

Bi₂O₃ added Mg₂TiO₄ (MTO) ceramics were prepared by conventional solid-state reaction method. The effect of Bi₂O₃ on the densification, microstructure and microwave dielectric properties of MTO ceramics was investigated. The Bi₂O₃ addition significantly lowered the densification temperature of MTO ceramics from 1450°C to 1250°C, which is attributed to the liquid phase effect and smaller initial particle sizes. The dielectric constant (ϵ_r) was not significantly changed; while the Q × f_o was tremendously influenced with Bi₂O₃ content. A fine combination of microwave dielectric properties (Q × f_o = 160,500 GHz, (at 10.48 GHz) and ϵ_r = 13.2) were obtained for the 1 wt.% Bi₂O₃ added MTO sample, sintered at 1250°C. Further, the microwave dielectric properties of the MTO ceramics showed significant dependent on relative density, average grain size and oxygen vacancies.

KEYWORDS:

• Sintering
• microwave
• dielectric properties

Acknowledgments

The author RKB acknowledges the assistance from DRDO. The authors acknowledge Prof. A. Mahanta, Department of Electronics and Electrical Engineering, IIT Guwahati, for helping microwave related measurements. One of the co-author T Santhosh Kumar acknowledges IIT (ISM) Dhanabad for providing Post Doctoral Fellowship.