低介电微波陶瓷的设计、制备及性能优化

发布时间：2018-05-21 14:53

  本文选题：微波介质陶瓷 + 低介电常数　； 参考：《桂林理工大学》2017年硕士论文

【摘要】：随着现代通信技术的飞速发展,微波技术向着更高频率的方向发展,同时微波电子元器件也不断呈现出高频化、集成化的特点,低介电微波介质陶瓷材料受到了越来越多的关注。本文系统研究了(1-x)Zn Al2O4-x Li4/3Ti5/3O4、Li4x/3Zn2-2x Ti1+2x/3O4、Li_(4x/3)Mg_(2-2x)Ti_(1+2x/3)O_4、Ba_4CuTi_(11)O_(27)等低介电微波介质陶瓷的制备及性能,探究了Li_2ZnTi_3O_8、Li_2MgTi_3O_8陶瓷的工艺优化,并对上述陶瓷与Ag电极的低温共烧进行了初步探讨。(1)利用固相反应法制备了(1-x)ZnAl_2O_(4-x)Li_(4/3)Ti_(5/3)O_4(ZALT)(x=0.2,0.4,0.6,0.8)微波介质陶瓷。X射线衍射数据显示,Li_4Ti_5O_(12)和Zn Al2O4不能形成固溶体。随着x从0.2增加至0.8,ZALT陶瓷的相组成发生了如下变化:(Zn Al2O4和Li_2ZnTi_3O_8,x=0.2,0.4)→(Zn Al2O4,Li_2ZnTi_3O_8和Li_4Ti_5O_(12),x=0.6)→(Li_2ZnTi_3O_8和Li_4Ti_5O_(12),x=0.8)。随着x值的增加,烧结温度从1275°C降低到1075°C。ZALT陶瓷的微波介电性能表现为,ε_r:11.0~29.0,品质因数Q×f值:6,090~65,580 GHz,温度系数τ_f值:-62.9~-5.7 ppm/°C。(2)通过传统的固相法分别制备了Li_(4x/3)Zn_(2-2x)Ti_(1+2x/3)O_4(0.2≤x≤0.8)(LZT)、Li_(4x/3)Mg_(2-2x)Ti_(1+2x/3)O_4(0.2≤x≤0.8)(LMT)微波介质陶瓷。XRD分析表明,当0.2≤x≤0.4时,样品分别表现为Zn2Ti O4结构、Mg2Ti O4结构的固溶体,当0.6≤x≤0.8时,固溶体的结构分别改变为Li_2ZnTi_3O_8结构、Li_2MgTi_3O_8结构。随着x值的增加,陶瓷的烧结温度有所下降,其温度系数τ_f值从较大的负值增加到接近于零。LZT、LMT陶瓷均表现优异的微波介电性能(LZT:ε_r:12.6~26.3,Q×f:7930130560GHz,τ_f:-49.0~-14.0ppm/°C;LMT:ε_r:11.6~29.3,Q×f:22000～172670GHz,τ_f:-48.9~-3.9 ppm/°C)。此外,LZT(x=0.8)、LMT(x=0.8)分别可以在925℃、950 ℃与Ag粉具有很好的化学兼容性。(3)系统研究了原材料预处理对Li_2ZnTi_3O_8陶瓷、Li_2MgTi_3O_8陶瓷的显微结构、烧结特性及微波介电性能的影响,恰当的原材料预处理使得陶瓷在一个较低的温度区间(Li_2ZnTi_3O_8:950~1050 ℃,Li_2MgTi_3O_8:925~1075 ℃)获得高的品质因数,改善了陶瓷的烧结特性,降低其烧结温度,而且在一定程度上也对其τ_f值进行了调节。950 ℃烧结的Li_2ZnTi_3O_8陶瓷与925 ℃烧结的Li_2MgTi_3O_8陶瓷均能够能与Ag共烧兼容,并表现出优异的微波介电性能:ε_r=25.8,Q×f=74,200 GHz,τ_f=-13 ppm/℃(Li_2ZnTi_3O_8);ε_r=27.0,Q×f=58,480 GHz,τ_f=0.45ppm/℃(Li_2MgTi_3O_8)。(4)采用固相反应法制备了新型Ba_4CuTi_(11)O_(27)低烧微波介质陶瓷,通过Rietveld法对975 ℃烧结的样品进行XRD精修,可以确定这个纯化合物为单斜晶相,空间群为C12/m,其相结构为Ba_4CuTi_(11)O_(27),可靠因子分别为RWP=6.1%,RP=4.6%,RB=3.1%。当烧结温度为975 ℃时,陶瓷具有较为优异的微波介电性能:ε_r~36.3,Q×f~15,040 GHz,τ_f~11.9ppm/℃。Ba_4CuTi_(11)O_(27)在950 ℃时也表现出较好的微波性能,并且可以与Ag电极表现出良好的化学兼容性。
[Abstract]:With the rapid development of modern communication technology, microwave technology is developing to a higher frequency. At the same time, microwave electronic components have the characteristics of high frequency and integration. Low dielectric microwave dielectric ceramics have attracted more and more attention. In this paper, we have systematically studied the preparation and properties of low-dielectric microwave dielectric ceramics such as Li4x3Zn2-2x Ti1 2x3O4L, Li4x / Zn / 3Zn2-2x, Li4x / 3Zn2-2O4, Li-x / 3Mg-P / 3M / T, 4 x / 3Mg-TiV, 12x- / 3mq, Ba4CuTiV, etc., and investigated the technological optimization of Li2ZnTi3O8 / Li2ZnTi3O8. The low temperature co-firing of the above mentioned ceramics and Ag electrode was discussed. 1) the solid state reaction method was used to prepare 1-xZnAl2O2O-4-xAl2O-4 / 3tititititititi-5 / 3O4 / 5 / 3O4ZALTX 0.2O0.40.60.8. the microwave dielectric ceramics. X-ray diffraction data show that Li4Ti5OSAS12) and Zn Al2O4 can not form solid solutions. As the phase composition of ZALT ceramics increases from 0.2 to 0.8, the following changes have taken place in the phase composition of the ZALT ceramics: Zn / Zn Al2O4 and Li _ 4Ti _ 5i _ 3O _ 3O _ (0.2o).) Zn Al _ 2O _ 4o _ 3O _ 8 and Li _ 4Ti _ 5O _ 3O _ 2O _ 8 and Li4Ti5O _ (0. 6). As the x value increases, 鐑х粨娓╁害浠，

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