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