Effect of Microwave Sintering on the Properties of 0.95(Ca0.88Sr0.12)TiO₃⁻0.05(Bi0.5Na0.5)TiO₃ Ceramics.

Lei Tian,He Wang,Chunying Shen,Jing Nan

doi:10.3390/ma12050803

Abstract

Perovskite ceramics are a common microwave dielectric material, but the development and application of this material has been limited by the high, positive resonance frequency temperature coefficient and sintering temperature. Therefore, adjusting the temperature coefficient of the resonance frequency and reducing the sintering temperature have become important research directions. In this work, 0.95(Ca0.88Sr0.12)TiO3–0.05(Bi0.5Na0.5)TiO3 ceramics (referred to as 0.95CST-0.05BNT) were prepared by standard solid-state reaction and microwave sintering. Microwave sintering greatly shortened the sintering period and holding time. Moreover, the 0.95CST–0.05BNT ceramics showed more uniform grain size distribution, and microwave sintering reduced energy consumption in the experiment. Therefore, the temperature coefficient of the resonance frequency of MWS ceramics was reduced by 119 × 10−6 /℃. All of the ceramics, which were sintered at 1300 °C for 40 minutes, showed optimal microwave dielectric properties: εr = 187.6, Q × f = 8958 GHz, and τf = +520 × 10−6 /°C.

Highlights

With the rapid development of wireless communication technology, microwave dielectric materials have been extensively used in many microwave-integrated circuits, such as dielectric oscillators, filters, and other devices [1]
Microwave dielectric ceramics require three key properties, including dielectric constant, a high Q × f value, and a low-temperature coefficient of resonance frequency (τ f ) to maintain the temperature stability of microwave ceramics [2,3]. Owing to their high dielectric properties, the microwave ceramics have been in high demand in recent years
Compared with conventional sintering methods, we summarize the characteristics of several microwave sintering methods as follows

Summary

Introduction

With the rapid development of wireless communication technology, microwave dielectric materials have been extensively used in many microwave-integrated circuits, such as dielectric oscillators, filters, and other devices [1]. Microwave dielectric ceramics require three key properties, including dielectric constant (εr ), a high Q × f value, and a low-temperature coefficient of resonance frequency (τ f ) to maintain the temperature stability of microwave ceramics [2,3]. Owing to their high dielectric properties, the microwave ceramics have been in high demand in recent years. (1–x)(Ca0.88 Sr0.12 )TiO3 -x(Bi0.5 Na0.5 )TiO3 ceramics were prepared by the standard solid-state sintering method. 0.95CST–0.05BNT ceramics were prepared by standard solid-state and microwave sintering. Microwave sintering greatly shortened the sintering period and reduced the energy consumption

Experimental

Results and and Discussion

Conclusions