Bi2O3掺杂对 Ag(Nb0.8Ta0.2)O3陶瓷结构和介电性能的影响(英文)

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第30卷第3期 2014年3月 无 机 化 学 学 报 CHINESE JOURNAL OF INORGANIC CHEMISTRY V0l_30 No.3 649—653 

Bi2O3掺杂对Ag(Nb。.8Ta。.2)O3陶瓷结构和介电性能的影响 

肖 谧 杨 朝 钟小蓉席芳芳 

(天津大学电子信息工程学院,天津300072) 

摘要:本文研究了Bi20 掺杂对Ag(Nbo.aTao.2)O,陶瓷的结构和介电性能的影响。X射线衍射(xRD)结果表明,Bi:O,的掺杂可以使 

陶瓷中Ag 被还原并析出,且银析出的量随Bi203掺杂量的增加而不断增加,这可能源自于Bi 对Ag 的取代。在一定范围内增大 

Bi20 掺杂量可提高Ag(Nb ffao. ̄)O,陶瓷的室温介电常数,降低介电损耗,并使温度系数向负值方向移动。当Bi20,的掺杂量约为 3.5wt% ̄,样品具有较大的介电常数 =672)和较小的介电损耗(ta =7.3x10- ̄)。 

关键词:ANT;Bi203;掺杂;Ag析出;高介电常数 中图分类号:TM22+5 文献标识码:A 文章编号:1001—4861(2014)03—0649—05 

DoI:10.11862/CJIC.2014.054 

Influence of Bi203 on the Structure and Dielectric Properties of Ag 

XIAO Mi rANG Zhao ZHONG Xiao—Rong XI Fang—Fang 

(School ofElectronic Information Engineering,Ti删in University,Ti吼Jin 300072,China) 

Abstract:The effect of Bi203 doping on the structure and dielectric properties of Ag(Nb0.sT 2)03 ceramics was 

investigated in this paper.The results of X-ray diffraction(XRD)showed that the doping of Bi203 could tend to 

accelerate the reduction of Ag,which may originate from the substitution of Bi for Ag .A certain doping amount 

0f Bi203 would result in the increase of dielectric constant,and the decrease of dielectric 1OSS of Ag(Nbnffao. ̄)O3 

ceramics at room temperature,and making temperature coefficient shift for negative direction.The reason for the 

improvement of dielectric properties was also discussed.When the amount of Bi2O3 was about 3.5wt%,the sample 

had the best dielectric properties,larger permittivity( ̄=672)and smaller dielectric loss(tan ̄=7.3x10- ̄). 

Key words:ANT;Bi2O3;doping;Ag precipitation;high dielectric constant 

0 Introduction 

Dielectric materials for microwave dielectric 

resonators should have a high dielectric permittivity 8, 

a large quality factor Q,and a temperature coefficient of the resonant frequency f c]ose to zero【 .Compreh— 

ensive study on the dielectric properties of microwave, 

sub—millimeter to infrared spectroscopy翻has proved 

that silver niobate-tantalate AgNb1_xTa ̄O3(ANT)has a 

high potential in microwave application 5j.In ANT 

收稿日期:2013.07.03。收修改稿日期:2013—09—26。 通讯联系人。E-mail:xiaomi@tju.edu.cn;会员登记号:E190004927S。 there is a negligible dielectric dispersion for a very 

broad frequency range from 1 kHz up to approxi— 

mately 100 GHzt6-7 ̄.The test performed in the 1 GHz 

region indicated a permittivity of 430,a temperature 

coefficient of permittivity<5.0xl0 ℃~.and a Q value 

of 700 for the AgNb0.65Tao.3503-AgNbo.ssTao.6503 composite. 

Such properties will allow US to produce electronic 

components with a significantly reduced size and/or a 

much—increased capacity嘲. 

ANT ceramic has a structure of perovskit

e.The 650 无机化学学报 第30卷 

polarizability of the ions can be strongly influenced by 

the substitutions of the ions at A or B sites in 

perovskite structure.In recent years,investigations of 

the effects of different ions on the dielectric properties 

of ANT ceramics were undertaken and considerable 

progresses have been obtained.The ANT ceramic 

can get a more ideal temperature characteristics by 

substituting alkali metal ions such as K and Na for Ag 圳.and the substitution of Li for Ag will bring a 

strong ferroelectricity【l1j.Doping of Sb205 can decrease 

the sintering temperature and the substitution of Sb at B site can improve dielectric properties【 .A proper 

amount of Bi203 substitution in the Ag(NbxTa1 O3 also have achieved good resultsl 31.However.the essence of 

improvement brought by Bi203 in the dielectric 

properties of ANT ceramic was not sufficiently recog- 

nized.In this paper,the effects of Bi2O3 on dielectric 

properties of ANT ceramic and corresponding reason 

were dj scussed. 

1 Experimental 

The samples of ANT ceramic doped with Bi2O3 

were prepared using traditional solid-state reaction 

method.NbzO5 and Ta2O5(99.99%)were mixed on 

the molar ratio of 80:20.The mixtures were ball 

milled.dried and then calcined at l 200℃.Ag,O was 

added to the calcined(NbnsTao.2)205 according to the 

chemical formula of Ag(Nbnffao2)O3,and different 

proportions of Bi203(0.5wt%,1.5wt%,2.5wt%,3.5wt%, 

4.5wt%,5.5wt%,7wt%,10wt%)were added respecti- 

vely.The mixtures were ball milled,dried and calcined 

at 950 cC.The resultant was ball milled again.After 

drying,the final powders were pressed into disks of 

10 mm in diameter and 1mm in thickness under a 

pressure of 10 MPa.and were then sintered at l 080— 

1 1 30℃.After silver electrode was formed.dielectric 

lOSS tan8 and capacitance C of samples were measured 

at 1 MHz using HP4278A RLC tester.The temperature 

coefficient of capacitance (TCC)was measured 

associated with an oven (GZ—ESPEC,Guangzhou, 

China)and an HM 27001 Capacitor C—T Meter Mode1. 

The TCC was measured in the temperature range of