六方晶鈦酸鋇Ba(Ti1-xRx)O3陶瓷(R = Mn、Fe、Co、Ni、Zn、Mg、In)之緻密化行為、微結構及微波介電特性

Densification, Microstructure Evolution and Microwave Dielectric Properties of Hexagonal Ba(Ti1-xRx)O3 Ceramics (R = Mn、Fe、Co、Ni、Zn、Mg、In)

許雅琪(hsu ya chi)

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)

https://doi.org/10.6841/NTUT.2006.00246

摘要

鈦酸鋇(BaTiO3)陶瓷基之鐵電材料在介電陶瓷電容器、熱敏電阻(PTCR)電熱調節器、化學感測器以及壓電元件上已有許多應用。在過去數十年的研究中，主要都是著重在正方晶鈦酸鋇(t-BaTiO3)的鐵電性質上。然而，對於高溫相六方晶同素異形體鈦酸鋇(h- BaTiO3)的研究卻不常出現在文獻中，特別是關於其物理特性更是鮮有報導。因此，本研究主要是利用傳統之固態反應法，添加不同元素以穩定高溫相之六方晶鈦酸鋇，並探討添加不同元素之成份配比對六方晶鈦酸鋇之緻密化行為、微結構變化及微波介電特性的影響。
實驗結果顯示，Ba(Ti1-xRx)O3陶瓷摻雜Mn、Fe、Co、Ni、Zn、Mg、In等元素均能獲得h-BaTiO3相，然而由於每個元素對於BaTiO3之溶解度不同，因此添加的量過多則會生成二次相。其中h-Ba(Ti0.65Mn0.35)O3陶瓷(介電常數：41.2；品質因子：14300及共振頻率溫度係數：18.6 ppm/oC)以及h-Ba(Ti0.50Mn0.50)O3陶瓷(介電常數：32.8；品質因子：6450及共振頻率溫度係數：3.6 ppm/oC)最具有六方晶Ba(Ti1-xMnx)O3於介電共振器上應用之潛在可能性。除此之外，其他陶瓷系統，由於其共振頻率溫度係數過大，因此無法作為商業上之應用。

關鍵字

鈦酸鋇 ； 六方晶 ； 介電共振器 ； 微波介電性質

並列摘要

Barium titanate, BaTiO3, based ceramics have many applications in capacitors, positive temperature coefficient of resistance （PTCR）, chemical sensors, and piezoelectric devices. Most researches to date have focused on the low temperature tetragonal polymorph (t-BaTiO3), due to it possesses ferroelectric properties. However, up to date, few works have attempted to explore the possible application for the high temperature 6H-hexagonal polymorph (h-BaTiO3). There are only a few reports about its physical properties. In this study, solid-state reaction method was used to dope different dopants to stabilize hexagonal BaTiO3. The influences of dopants on the densification, microstructure evolution, and microwave dielectric properties of hexagonal BaTiO3 were discussed.
Experimental results show that the Ba(Ti1-xRx)O3 ceramics doped with Mn, Fe, Co, Ni, Zn, Mg and In exhibit the hexagonal BaTiO3 phase after sintering. However, because of the differences in the solid solution limits, excess dopants will result in a second phase. Among all systems, h-Ba(Ti0.65Mn0.35)O3 ceramic (dielectric constant：41.2，Q factor：14300, and the temperature coefficient of the resonance frequency：18.6 ppm/oC) and h-Ba(Ti0.50Mn0.50)O3 ceramic (dielectric constant：32.8, Q factor：6450, and the temperature coefficient of the resonance frequency：3.6 ppm/oC) have the best microwave dielectric properties and the potential for application in dielectric resonators. The other ceramic systems, due to this high temperature coefficient of the resonant frequency（TCF）, can not be used in commercial applications.

並列關鍵字

BaTiO3 ； Hexagonal ； Dielectric resonator ； Microwave dielectric properties

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