Influence of B₂O₃ Additions and Sintering Temperature on the Dielectric Properties of La_2.98/3Sr_0.01(Mg_0.5Sn_0.5)O₃ Ceramics at Microwave Frequency

Abstract

In this study, the microwave dielectric properties of La_2.98/3Sr_0.01(Mg_0.5Sn_0.5)O₃ ceramics prepared by the conventional solid-state method had been investigated for application in mobile communication. B₂O₃ was selected as a liquid sintering aid to reduce the sintering temperature of La_2.98/3Sr_0.01(Mg_0.5Sn_0.5)O₃ ceramics. It was found that with 0.25 wt% B₂O₃ additive, the X-ray diffraction patterns of the La_2.98/3Sr_0.01(Mg_0.5Sn_0.5)O₃ ceramics exhibited no significant phase difference at different sintering temperatures from 1350 to 1500°C. The maximum values of the dielectric constant and the quality factor (Q × f) could be obtained when the La_2.98/3Sr_0.01(Mg_0.5Sn_0.5)O₃ with 0.25 wt% B₂O₃ additive were sintered at 1450°C for 4h. The temperature coefficient of resonant frequency τ _f (−77.0 ppm/°C) was measured of La_2.98/3Sr_0.01(Mg_0.5Sn_0.5)O₃ ceramics with 0.25 wt% B₂O₃ sintered at 1450°C for 4 h.

Keywords:

• La_2.98/3Sr_0.01(Mg_0.5Sn_0.5)O₃
• dielectric constant
• quality factor
• temperature coefficient of resonant frequency

Acknowledgment

This work was supported by the National Science Council of the Republic of China under Grant NSC 98-2622-E-262-009.