BaO-R2O3-TiO2低溫燒結微波陶瓷

Low Temperature Sintering of BaO-R2O3-TiO2 Microwave Ceramics

董憲澤(Shien-Tue Tung)

指導教授 ： 王錫福

國立臺北科技大學/工程學院/材料及資源工程系所/碩士(2005年)

摘要

BaO-R2O3-TiO2系列之微波介電陶瓷材料具有較高的介電常數值(εr )，其介電常數介於70 ~ 100之間，可有效縮小元件之體積。本研究之Ba6-3yR8+2yTi18O54微波陶瓷是利用固態反應法加以合成，分別藉由置換Ba與鑭系離子以及探討Nd與Sm稀土族元素之成份配比對燒結緻密化、微結構及微波介電特性的影響。結果顯示，Ba4.5(Sm1-xNdx)9Ti18O54的系統中於x = 0時，具有優良的微波介電性質：εr = 76.5, Q×f= 3500GHz, τf = 3.8 ppm/℃；而Ba5.1(Sm1-xNdx)8.6Ti18O54的系統於x = 0.25時，有優良的微波介電性質：εr = 85.2, Q×f= 2200GHz, τf = -0.8 ppm/℃；而Ba3.9(Sm1-xNdx)9.4Ti18O54的系統中於x = 0.5時，具有優良的微波介電性質：εr = 81.8, Q×f= 11050GHz, τf = 19.8 ppm/℃。藉由這些結果，使用以Ba4.5(Sm1-xNdx)8.6Ti18O54為基材添加10wt% glass於x=0.7，燒結溫度在1065℃可達到理論密度93%以上，另外燒結溫度為1115℃時具有優良的微波介電性質：εr =63.6，Q×f=5192 GHz，τf =9.6 ppm/℃。
在玻璃添加劑方面，添加微量MnCO3及Bi2O3可提高緻密行為、介電常數及降低τf值而趨近於零。另外粉體粒徑越細可促進燒結緻密化在較低溫達成，進而增加介電常數值，縮小Q×f值範圍。

關鍵字

微波陶瓷 ； 介質共振器 ； 介質濾波器 ； 介電性質

並列摘要

The dielectric properties of BaO-R2O3-TiO2 ceramic system possesses a high dielectric constant (70 – 100), which are miniaturization of the dimensions of devices. In this study, the BaO-R2O3-TiO2 ceramics were prepared by a solid reaction method with replacement of lanthanide series by barium. The effects of composition and processing on the densification behavior, microstructural evolution and microwave dielectric properties of BaO-R2O3-TiO2 ceramics were investigated. The results exhibited that the Ba4.5(Sm1-xNdx)9Ti18O54 solid solutions with x = 0 had excellent dielectric properties (εr = 76.5, Q×f= 3500GHz, τf = 3.8 ppm/℃). In addition, Ba5.1(Sm1-xNdx)8.6Ti18O54 solid solutions with x = 0.25 also showed excellent dielectric properties (εr = 85.2, Q×f= 2200GHz, τf = -0.8 ppm/℃ ). Furthermore, Ba3.9(Sm1-xNdx)9.4Ti18O54 solid solutions with x = 0.5 also showed excellent dielectric properties (εr = 81.8, Q×f= 11050GHz, τf = 19.8 ppm/℃ ).The Ba4.5(Sm1-xNdx)8.6Ti18O54 solid solutions（x = 0.7）with addition of 10wt%glass sintered at the sintering temperature of 1115℃ possesses excellent dielectric properties ofεr = 63.6, Q×f= 5192GHz, τf = 9.6 ppm/℃.
Further additions of MnCO3 and Bi2O3 in glass could enhance the densification of ceramics, increase the permittivity and obtain a near zero of temperature coefficient of the resonant frequency. Besides, reducing the particle size could promote the densification of ceramics at lower temperature, increase the dielectric constant and narow down the range of Q×f value.

並列關鍵字

Microwave ceramics ； Dielectric resonator ； Dielectric filter ； Dielectric properties

參考文獻

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