新型钨锰铁矿型微波介质陶瓷性能及低温烧结研究

发布时间：2018-04-21 05:22

本文选题：微波介质陶瓷 + MgZrNb_2O_8　；参考：《浙江大学》2015年博士论文

【摘要】：开发新型超低损耗的微波介质陶瓷材料一直是材料科学领域的研究热点。最近,一种钨锰铁矿型AZrNb208陶瓷吸引了广大研究者的目光。该类陶瓷是一种中介电常数微波介质材料,具有超低介电损耗。然而该类陶瓷的烧结温度高于1200℃,很难满足微波器件应用的要求。目前有关其低温烧结的研究鲜有报道。本文首先对/AZrNb2O8(A:Mg、Zn、Co)微波介质陶瓷的烧结工艺、晶体结构及介电性能进行了研究。然后对该陶瓷体系进行了离子取代、低温烧结,以及与Ag、Ag/Pd电极的化学兼容性的研究。主要工作及结果如下：(1)优化了MgZrNb2Og8、ZnZrNb2O8、CoZrNb2O8三种微波介质陶瓷的烧结工艺,深入研究了陶瓷的微观结构与介电性能的关系。其中MgZrNb2O8最优的微波介电性能为：εr=25.67,Qf=109400GHz, τf=-48.78 ppm/℃(1325℃); ZnZrNb2O8最优的微波介电性能为：εr=28.78, Qf=81520GHz, τf=-52.95 ppm/℃ (1200℃); CoZrNb2O8最优的微波介电性能为：εr=26.41,Qf=44766GHz,τf=-44.28ppm/℃ (1225℃)。利用Rietveld结构精修测定了晶体结构信息,揭示了离子极化率、原子堆积密度、氧八面体畸变对介电常数、品质因素和频率温度系数的影响。(2)制备了Mg1-xZnxZrNbaO8(x=0.1、0.3、0.5、0.7、0.9)微波介质陶瓷。ZnO的引入能够促进Mg1-xZnxZrNb2O8陶瓷的烧结,降低体系烧结温度。研究发现Mg0.5Zn0.5ZrNb208为单相,同样具有钨锰铁结构,该陶瓷具有较宽的烧结温度范围(1175℃-1275℃),在1200℃烧结的样品具有优异的介电性能：εr=27.24,Qf=75399GHz, τf=-63.88ppm/℃。利用Rietveld结构精修测定了Mg0.5Zn0.5ZrNb2O8的晶体结构和相关结构信息,并且研究了不同Mg/Zn摩尔比对体系晶体结构、微观形貌及介电性能的影响。(3)制备了Zn1-xCoxZrNb2O8(x=0.1、0.3、0.5、0.7、0.9)陶瓷。所有组分的陶瓷在1175℃-1250℃温度范围都具有良好的烧结特性,体积相对密度都在94%以上。通过Rietveld结构精修揭示了Zn1-xCoxZrNb2O8体系的晶体结构特点,并研究了不同Zn/Co摩尔比对体系微观形貌及介电性能的影响。介电常数和Qf值均随着Co含量增加逐渐降低,这与体系离子极化率和原子堆积密度变化有关。Zn1-xCoxZrNb2O8陶瓷具有良好的介电性能(εr=26.59～26.1; Qf=45146～65290GHz; τf=-57.13～-44.28ppm/℃)。(4)研究了BaCu(B2O5)助剂对ZnZrNb2O8陶瓷烧结特性、物相组成及介电性能的影响。当BaCu(B2O5)添加量少于3wt%时,体系为纯ZnZrNb2O8相。过量的BaCu(B2O5)会导致体系出现少量的Ba3Nb8O21、BaNb2O6杂相。由于液相烧结的原因,BaCu(B2O5)的加入能将ZnZrNb2O8陶瓷烧结温度由1200℃降至950℃。添加3wt% BaCu(B2O5)的ZnZrNb2O8陶瓷在950℃烧结4h所得的样品具有优良的微波介电性能：εr=28.4, Qf=56720GHz, τf=-52.8ppm/ ℃,而且陶瓷与Ag电极具有良好的化学兼容性,可调节之后有望应用于LTCC技术。(5)研究了BaCu(B2O5)助剂对MgZrNb2O8陶瓷烧结特性、物相组成及介电性能的影响。少量BaCu(B2O5)的加入引入了一定量的液相,促进了MgZrNb2O8陶瓷的烧结,能将烧结温度由1325℃降至1100℃。然而,当BaCu(B2O5)添加量超过2wt%时,体系出现了Ba3Nb8O21杂相。添加2wt% BaCu(B2O5)的 MgZrNb2O8陶瓷在1100℃烧结所得的样品具有优异的微波介电性能：εr=25.96,Qf=65064GHz, τf=-47ppm/℃,而且陶瓷与Ag/Pd电极具有良好的化学兼容性。
[Abstract]:The development of a new type of ultra-low loss microwave dielectric ceramics has been a hot spot in the field of material science. Recently, a kind of tungsten manganese iron type AZrNb208 ceramics has attracted the attention of the vast number of researchers. This kind of ceramics is a medium dielectric constant microwave dielectric material with ultra-low dielectric loss. However, the sintering temperature of this kind of ceramics is higher than 1200. It is difficult to meet the requirements for the application of microwave devices. At present, there are few reports about its low temperature sintering. First, the sintering process, crystal structure and dielectric properties of /AZrNb2O8 (A:Mg, Zn, Co) microwave dielectric ceramics were studied. Then the ceramic system was replaced by ion, low temperature sintering, and chemical compatibility with Ag, Ag/Pd electrode. The main work and results are as follows: (1) the sintering process of three kinds of microwave dielectric ceramics, MgZrNb2Og8, ZnZrNb2O8, CoZrNb2O8, was optimized. The relationship between microstructure and dielectric properties of ceramics was studied. The optimum microwave dielectric properties of MgZrNb2O8 were: epsilon r=25.67, Qf=109400GHz, tau f=-48.78 ppm/ C (1325 C); ZnZrNb2O8 most The excellent microwave dielectric properties are: epsilon r=28.78, Qf=81520GHz, tau f=-52.95 ppm/ C (1200 C); the optimum microwave dielectric properties of CoZrNb2O8 are: epsilon r=26.41, Qf=44766GHz, tau f=-44.28ppm/ C (1225 C). The crystal structure information is measured by Rietveld structure refinement, and the ion polarization, atomic accumulation density and oxygen eight surface body distortion are revealed. The influence of electrical constant, quality factor and frequency temperature coefficient. (2) the introduction of Mg1-xZnxZrNbaO8 (x=0.1,0.3,0.5,0.7,0.9) microwave dielectric ceramic.ZnO can promote the sintering of Mg1-xZnxZrNb2O8 ceramics and reduce the sintering temperature of the system. It is found that Mg0.5Zn0.5ZrNb208 is a single phase and has the structure of tungsten ferromanganese as well. The ceramic has a wider sintering. The temperature range (1175 -1275 C), the sample sintered at 1200 C has excellent dielectric properties: epsilon r=27.24, Qf=75399GHz, tau f=-63.88ppm/ C. The crystal structure and related structure information of Mg0.5Zn0.5ZrNb2O8 are measured by Rietveld structural refinement, and the crystal structure, micromorphology and dielectric properties of different Mg/Zn molar ratio system have been studied. (3) Zn1-xCoxZrNb2O8 (x=0.1,0.3,0.5,0.7,0.9) ceramics were prepared. The ceramics of all components had good sintering characteristics at the temperature range of 1175 C -1250 C and the volume relative density was above 94%. The crystal structure characteristics of the Zn1-xCoxZrNb2O8 system were revealed through the Rietveld structure refinement, and the different Zn/Co molar ratio pairs were studied. The influence of Micromorphology and dielectric properties. The dielectric constant and Qf value gradually decrease with the increase of Co content, which is related to the good dielectric properties of.Zn1-xCoxZrNb2O8 ceramics (epsilon r=26.59 ~ 26.1; Qf=45146 to 65290GHz; tau f =-57.13 ~ -44.28ppm/). (4) studied BaCu (B2O5) assistance. The effect of the agent on the sintering characteristics, phase composition and dielectric properties of ZnZrNb2O8 ceramics. When the addition of BaCu (B2O5) is less than 3wt%, the system is pure ZnZrNb2O8 phase. Excessive BaCu (B2O5) will result in a small amount of Ba3Nb8O21, BaNb2O6 heterozygosity. The addition of BaCu (B2O5) can reduce the sintering temperature of ZnZrNb2O8 ceramics from 1200 degrees to the cause of liquid phase sintering. At 950 C, the samples obtained by adding 3wt% BaCu (B2O5) ZnZrNb2O8 ceramics at 950 C for 4H have excellent microwave dielectric properties: epsilon r=28.4, Qf=56720GHz, tau f=-52.8ppm/ C, and the good chemical compatibility between the ceramics and Ag electrodes, and can be applied to LTCC technology after adjustment. (5) a study of BaCu (B2O5) auxiliaries to the ceramics The effect of sintering characteristics, phase composition and dielectric properties. A small amount of BaCu (B2O5) was added to a certain amount of liquid phase, which promoted the sintering of MgZrNb2O8 ceramics and reduced the sintering temperature from 1325 to 1100. However, when the addition of BaCu (B2O5) was more than 2wt%, the system appeared Ba3Nb8O21 heterozygous. The MgZrNb2O8 ceramics adding 2wt% BaCu (B2O5) was 110. The samples obtained at 0 C have excellent microwave dielectric properties: epsilon r=25.96, Qf=65064GHz, tau f=-47ppm/ C, and the good chemical compatibility between the ceramics and the Ag/Pd electrode.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TQ174.1

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