低溫燒結BaO-R2O3-Bi2O3-TiO2之微波介電陶瓷

Low Temperature Sintering of BaO-R2O3- Bi2O3-TiO2 System Microwave Dielectric Ceramics

吳文榮(Wen Jung wu)

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(2006年)

摘要

BaO-R2O3-Bi2O3-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100 ~ 150之間，可有效縮小電子元件之體積，此系統可作為微波濾波器和共振器。本研究之Ba(Sm0.24Nd0.56Bi0.2)9Ti18O54微波陶瓷是利用固態反應法加以合成並添加不同比例之玻璃，在1000~1200℃進行燒結。結果顯示，Ba(Sm0.24Nd0.56Bi0.2)9Ti18O54微波陶瓷添加4wt%玻璃在1100℃燒結後即可達到燒結緻密化，其介電常數為81.9、Qxf為1000~3000、及τf =21.3 ppm/℃。另外，在BaO-R2O3-Bi2O3-TiO2微波陶瓷中，利用Nd、La、Bi置換Sm離子並探討成份之配比對其燒結緻密化溫度、顯微結構及介電特性的影響。
實驗結果顯示介電粉中的氧化鉍增加時，會增加基材之液相燒結，降低其燒結緻密化溫度。介電常數及τf會隨著氧化鉍增加而呈現上升趨勢。Nd、La離子替換介電粉中的Sm離子，主要是增加其介電常數，但會提高其τf。Ba4.5(Sm0.225Nd0.368La0.157Bi0.25)9Ti18O54介電粉在1100℃燒結後即可達到緻密化，其具備良好的微波介電性質(εr=91.7、Qxf為900~1500、及τf =27.3 ppm/℃)。

關鍵字

微波陶瓷 ； 介電性質

並列摘要

BaO-R2O3-Bi2O3-TiO2 ceramics have high dielectric constants (εr=100~150), which can minimize the size of devices. This system are widely used in commercial microwave filters and oscillators. Ba4.5(Sm0.24Nd0.56Bi0.2)9Ti18O54 ceramics was made by the solid-state reaction. The ceramics were sintered in the temperature range of 1000~1200℃. The result showed that Ba4.5(Sm0.24Nd0.56Bi0.2)9Ti18O54 ceramics with 4wt% glass sintered at 1100℃ had sintering density of 5.36 g/cm3, dielectric constant of 81.9, Q x f of 3677 and τf of 21.3 ppm/℃. The effects of composition on the densification, microstructure and microwave dielectric properties of BaO-R2O3-Bi2O3-TiO2 ceramics were disscussed.
Additions of Bi2O3 in BaO-R2O3-Bi2O3-TiO2 ceramics improve their densification and permittivity, but they poison their τf. Nd / La co-substitution for Sm in BaO-R2O3-Bi2O3-TiO2 ceramics enhance permittivity, but degrade τf. The result exhibited that Ba4.5(Sm0.225Nd0.368La0.157Bi0.25)9Ti18O54 ceramics with 4wt% glass sintered at 1100℃ obtain a high densiy and good microwave properties (εr =91.7, Q×f =900~1500, τf =27.3 ppm/℃).

並列關鍵字

Microwave ceramics ； Dielectric properties

參考文獻

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