复相弛豫铁电陶瓷的相组成与介电性能

采用两相混合烧结法在Ｐｂ（Ｚｎ１／３Ｎｂ２／３）Ｏ３－ＢａＴｉＯ３－ＰｂＴｉＯ３系统中制备了弛豫铁电陶瓷材料，相组成研究表明，该陶瓷具有两相共存的复相结构，对复相陶瓷的介电性能进行了研究，结果表明，复相结构可有效地改善弛豫铁电陶瓷的介温特性、频率特性和介质老化性能。     

纳米BaTiO3及其陶瓷材料的特殊物性的研究

报导了硬脂酸凝胶法制备的ＢａＴｉＯ３纳米晶及烧制的陶瓷材料的特殊物性，用Ｘ射线衍射、高分辨透射电镜、Ｘ荧光光谱、表面光电子能谱、介电谱、热释电谱研究了纳一粉及陶瓷材料的晶体结构，晶粒尺寸体相和表面相组份及铁电性能。结果表明，所有样品在室温下均为立方结构，没有铁电性，陶瓷样品在低温下具有铁电性。并发现纳米晶ＢａＴｉＯ３及陶瓷具有湿敏特性。     

制备介电体薄膜用MOCVD材料

制备介电体薄膜用ＭＯＣＶＤ材料阎圣刚，高占先，周科衍（大连理工大学，化工学院，大连１１６０１２）１．前言具有钙钛矿结构的ＢａＴｉＯ＿３、ＰｂＴｉＯ＿３、ＰＺＴ及ＬｉＮｂＯ＿３是很有价值的介电材料，近年来在电子学领域的应用发展迅速。强的介电体具有绝缘性...     

BaTiO3纳米晶热稳定性的研究

采用硬脂酸盐（ＳＡＧ）法合成了ＢａＴｉＯ３纳米晶材料，对其粒子尺寸和性能随着温度和时间的变化进行了详细的测试，并与溶胶凝胶（Ｓｏｌｇｅｌ）法合成的ＢａＴｉＯ３纳米晶进行了对比，结果表明：ＳＡＧ法合成的ＢａＴｉＯ３纳米晶具有良好的热稳定性。产生这种特殊性能的原因可能是ＢａＴｉＯ３纳米晶晶粒表面富Ｂａ引起的。     

Na1/2Bi1/2TiO3-BaTiO3系陶瓷压电性?及弛豫相变研究

系统研究了（１－ｘ）Ｎａ１／２Ｂｉ１／２ＴｉＯ３－ｘＢａＴｉＯ３（ｘ＝０．０２、０．０４、０．０６、０．０８、０．１０）无铅压电陶瓷系统的相界、材料压电性能,弛豫特性及相变．这个系统的陶瓷材料具有Ｋｔ／Ｋｐ较大,频率常数比较高等特点．Ｘ－ｒａｙ衍射结构分析发现此系统的相界在０．０４＜ｘ＜０．０６之间;材料的一些主要性能在相界附近达到极值．利用介电系数－温度曲线,并结合热激电流曲线对此系统的弛豫性进行研究和分析;初步研究了各配方组成的铁电－顺电的相变过程,发现在一定的组成范围内,材料在由铁电相向顺电相的转变过程中经历了一个过渡相区．     

Na1/2Bi1/2TiO3-BaTiO3系陶瓷压电性及弛豫相变研究

系统研究了（１－ｘ）Ｎａ１／２Ｂｉ１／２ＴｉＯ３－ｘＢａＴｉＯ３（ｘ＝０．０２、０．０４、０．０６、０．０８、０．１０）无铅压电陶瓷系统的相界、材料压电性能、驰豫特性及相变。这个系统的陶瓷材料具有Ｋｔ／Ｋｐ较大,频率常数比较高等特点,Ｘ－ｒａｙ衍射结构分析发现此系统的相界在０．０４〈ｘ〈０．０６之间;材料的一些主要性能在相界附近达到极值。利用介电系数－温度曲线,并结合热激电流曲线对此系统的驰豫性进     

铁磁性Mn—Zn,Ni—Zn铁氧体与铁电性BaTiO3复合材？…

本文研究了铁磁性Ｍｎ－Ｚｎ，Ｎｉ－Ｚｎ铁氧体与铁电性ＢａＴｉＯ３复合材料在１－１０００ＭＨｚ频段内的吸波能力。结果表明；随频率升高，Ｍｎ－Ｚｎ２铁氧ＢａＴｉ／Ｏ３和Ｎｉ－Ｚｎ铁氧体／ＢａＴｉＯ３复合材料的吸波能力逐渐增加；随Ｍｎ－Ｚｎ或Ｎｉ－Ｚｎ铁氧体含量增加，这两类复合材料的吸波能力也逐渐增加；相同配比时的Ｎｉ－Ｚｎ铁氧体／ＢａＴｉＯ３复合材料吸波能力大于Ｍｎ－Ｚｎ铁氧体／ＢａＴｉＯ３。     

CeO2掺杂BaTiO3基X7R材料的介温特性

研究了ＣｅＯ２与Ｎｂ２Ｏ５和Ｃｏ２Ｏ３共掺杂的ＢａＴｉＯ３基Ｘ７Ｒ材料的介温特性。系统在Ｘ７Ｒ温度范围内体现出高介（〉４０００）、稳定、低损耗（〈２％）的特点。介电温谱表明相同工艺条件下，ＣｅＯ２含量增加可提高室温介电常数和介电变化率；适当提高邓烧温度有助于介温谱的平化，且其介温特性表现出更为明显的多峰效应。系统可在１２２０～１２４０℃的较低温度下烧成。     

Pb掺杂BaO—Nd2O3—TiO2系微波介质陶瓷及其低频量方法的研究

初步研究了微波介质陶 Ｂａ３．７５Ｎｄ９．６Ｔｉ１８Ｏ５４在Ｐｂ掺杂后的显微组织与及晶体结构的变化，并验证了用低频介电测量数据估算微波介质陶瓷材料介电性质的可行性。研究结果表明，掺入少量Ｐｂ以后，Ｂａ３．７５Ｎｄ９．５Ｔｉ１８Ｏ５４介电陶瓷的微观结构有显著变化，介电性能，尤其是相对介电常数εｒ有明显提高。     

铌锌酸铅基陶瓷的铁电行为研究

采用具有改进ＳａｗｙｅｒＴｏｗｅｒ电路的全自动铁电体电滞回线测试系统，对（０．９ｘ）Ｐｂ（Ｚｎ１／２Ｎｂ２／３Ｏ３０．１ＢａＴｉＯ３ｘＰｂＴｉＯ３［（ｘ＝０．０５，０．１０，０．１５，简称ＰＺＮＢＴＰＴ（０．１／ｘ）］系列铁电陶瓷样品在０℃～１９０℃温度范围内强场下的极化强度进行了详细测试，并与其弱场介电行为对比，探讨了铁电宏畴微畴不同的强场极化特性，发现ＰＺＮＢＴＰＴ（１０／１５）铁电陶瓷样品的极化强度在自发正常铁电体弛豫型铁电体转变温度Ｔｎｒ下有一个增大过程。     

BSTO/Mg2SiO4/MgO复合材料的介电性能研究

采用传统的电子陶瓷制备工艺制备了BSTO／Mg2SiO4／MgO复合材料，并对样品的结构及其介电性能进行了表征与分析，讨论了Mg2SiO4／MgO掺杂对BSTO／Mg2SiO4／MgO复合材料结构和性能的影响．结果表明，与前其他掺杂改性的BSTO复合材料相比，BSTO／Mg2SiO4／MgO复合材料不仅可以在较低的温度烧结致密，而且在介电常数降低的同时，仍能保持较高的可调性，如BSTO／39wt％Mg2SiO4／17wt％MgO的介电常数εr为-80．21，在2kV／mm的直流偏置电场下，其可调性达到-12％，介电损耗为-0．003．     

Barium Titanate-Polymer Composites Produced via Directional Freezing

In this study, we use a freeze casting technique to construct ceramic-polymer composites in which the 2 phases are arranged in an electrically parallel configuration. By doing so, the composites exhibit dielectric constant (K) up to 2 orders of magnitude higher than that of composites with ceramic particles randomly dispersed in a polymer matrix. In this technique, an aqueous ceramic slurry was frozen unidirectionally to form ice platelets and ceramic aggregates that were aligned in the temperature gradient direction. Upon freeze-drying, the ice platelets sublimed and left the lamellar ceramic structure intact. The green ceramic body was fired to retain the microstructure, and then the space between ceramic lamellae was infiltrated with a polymer material. The finished composites exhibit the high dielectric constant (1000) of ferroelectric ceramics while maintaining the unique properties of polymer materials such as graceful failure, low dielectric loss, and high dielectric breakdown.     

Comparison of theoretical predictions and experimental values of the dielectric constant of epoxy/BaTiO<Subscript>3</Subscript> composite embedded capacitor films

Polymer/ceramic composites are the most promising embedded capacitor material for organic substrates application. Predicting the effective dielectric constant of polymer/ceramic composites is very important for design of composite materials. In this paper, we measured the dielectric constant of epoxy/BaTiO₃ composite embedded capacitor films with various BaTiO₃ particles loading for 5 different sizes BaTiO₃ powders. Experimental data were fitted to several theoretical equations to find the equation useful for the prediction of the effective dielectric constant of polymer/ceramic composites and also to estimate the dielectric constant of BaTiO₃ powders. The Lichtenecker equation and the Jayasundere-Smith equation were useful for the prediction of the effective dielectric constant of epoxy/BaTiO₃ composites. And calculated dielectric constants of the BaTiO₃ powders were in the range of 100 to 600, which were lower than the dielectric constant of BaTiO₃ bulk ceramics probably due to the presence of voids or pores.     

BCTZ-环氧树脂复合材料的制备和介电性能研究

采用固相反应法制备了Ba0.96 Ca0.04 Ti0.8 Zr0.2 O3 (BCTZ)陶瓷粉末,然后采用溶液混合,热压的方法制备了BCTZ-环氧树脂(Epoxy)复合材料,研究BCTZ-环氧树脂复合材料介电性能与陶瓷含量、测试频率和温度的关系.结果表明,BCTZ-环氧树脂复合材料具有高的介电常数(48.6)和低的损...     

The dielectric properties and dielectric mechanism of perovskite ceramic CLST/PTFE composites

Polytetrafluorethylene (PTFE) composites filled with perovskite (Ca,Li,Sm)TiO₃ (CLST) dielectric ceramic of various volume fractions filler up to 60% were prepared. The effects of volume fraction of ceramic filler on the microstructure and dielectric properties of the composites have been investigated. A comparative study of dielectric properties of experiment and modeling analysis has been carried out at high frequencies for the CLST/PTFE composites. The results indicate that both the dielectric constant and the dielectric loss increase with the filler. The CLST/PTFE composite with 40% ceramic has exhibited good dielectric properties: ε _r?=?7.92 (~10 GHz), tan δ?=?1.2?×?10^?3 (~10 GHz), and τ _f?=??45 ppm/°C. The dielectric properties are obviously better than most composites reported previously at high frequencies in the aspects of dielectric loss and thermal stability. The dielectric constant and dielectric loss of composites predicted by the Rother–Lichtenecker equation and the general mixing model are in good agreement with the experiment data when the volume fraction of ceramic is less than 40%. When the volume fraction of the ceramic is more than 40%, the deviation occurs. By introducing the correction factor, the theoretical values of the dielectric constant agrees well with the experimental values.     

1-3型水泥基压电复合材料的制备及性能

采用切割-浇注法, 以硫铝酸盐水泥为基体, 制备了1-3型水泥基压电复合材料。详细阐述了1-3型水泥基压电复合材料的制备过程; 研究了0.375Pb(Mg_1/3Nb_2/3)O₃-0.375PbTiO₃-0.25PbZrO₃压电陶瓷柱的宽厚比w/t对1-3型水泥基压电复合材料的压电性能、 介电性能和声阻抗的影响。结果表明: 压电陶瓷柱的宽厚比w/t对1-3型水泥基压电复合材料性能有很大影响, 随着w/t的增加, 其压电应变常数d₃₃、 机电耦合系数K_p与K_t、 机械品质因数Q_m、 介电常数ε_r和介电损耗tanδ均随着w/t的增加而减小, 而压电电压常数g₃₃值几乎不受w/t的影响。在压电陶瓷体积分数仅为22.72%的条件下, 调节压电陶瓷柱的宽厚比w/t至0.130, 可使复合材料的声阻抗与混凝土的声阻抗十分接近, 从而有效地解决了智能材料在土木工程中的声阻抗相容性问题。      

The influences of particle sizes on the dielectric properties of PEI/(Ba0.8Sr0.2)(Ti0.9Zr0.1)O3 composites

In order to investigate the embedded capacitors with higher capacitance value in the future, two technologies of increasing the dielectric constant of filler and decreasing the thickness of capacitors can be combined to develop a best method. For that, the high dielectric constant of (Ba0.8Sr0.2)(Ti0.9Zr0.1)O3 (BSTZ) ceramic powders with three different sizes (3 microm, 200 nm, and 100 nm) are used as the filler to mix with polyetherimide (PEI) to form the PEI/BSTZ composites. The dielectric constants and loss tangents of PEI/BSTZ composites with different contents of BSTZ ceramic powders are measured using the plate method. As the contents of BSTZ powders increase from 10 wt% to 70 wt%, the dielectric constants and loss tangents of PEI/BSTZ composites increase with the increase content of BSTZ ceramic powders, independent on the particle sizes. As the BSTZ content is less than and equal to 50 wt% and same loading ratio is used, the dielectric constants of PEI/200 nm-BSTZ and PEI/100 nm-BSTZ composites are large than those of PEI/3 microm-BSTZ composites. In this study, the Lichtenecker logarithmic mixing rule is also used to fit the measured results and predict the dielectric constants of PEI/BSTZ composites.     

低损耗ZrTi2O6填充PTFE复合基板性能

采用热压成型工艺,制备了一种低损耗ZrTi₂O₆陶瓷填充聚四氟乙烯（PTFE）的新型微波复合基板材料。采用介质谐振器法研究了ZrTi₂O₆/PTFE复合材料的微波介电性能（8~12 GHz）。结果表明,ZrTi₂O₆/PTFE复合材料的相对介电常数（ε _r）和介电损耗（tanδ）随着ZrTi₂O₆陶瓷体积分数（0~46%）的增加而增大,介电常数实验值与Lichtenecker模型预测值最吻合。ZrTi₂O₆/PTFE复合材料的热膨胀系数和介电常数温度系数随着ZrTi₂O₆陶瓷体积分数的增加而减小。46%的ZrTi₂O₆为较优填料比例,ZrTi₂O₆/PTFE的相对介电常数为7.42,介电损耗为0.0022（10 GHz）。     

Characterization and properties of an organic–inorganic dielectric nanocomposite for embedded decoupling capacitor applications

Polymer/aluminum nanocomposites have a high dielectric constant and a low dielectric loss because of the combined characteristics of polymer–ceramic (due to the insulating ceramic shell of an aluminum particle) and polymer–metal (due to the metal core of an aluminum particle) systems. In this work, an aluminum particle surface treatment was performed with an epoxide-functionalized silane coupling agent in order to further improve the dielectric properties and processibility of polymer/aluminum composites. Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analyzer (TGA) were used to characterize the aluminum particles before/after coupling agent treatment. It was found that the silane coupling agent was successfully grafted on the aluminum particle surface. Rheology studies of polymer/aluminum composites showed that the coupling agent treatment could significantly reduce the viscosity of the aluminum composites, which indicates coupling agent treatment can improve the processibility of aluminum composites at high filler loading levels. Dielectric properties, including the frequency responses and temperature coefficient of capacitance of the aluminum composites were studied with a dielectric analyzer (DEA). The microstructures of aluminum composites were characterized with a field emission scanning electron microscope (SEM). It was found that a coupling agent treatment can improve the aluminum particle distribution and thereby enhancing the dielectric constant of aluminum composites.     

TEOS surface modification of CLST ceramic particles for PTFE-based composites

PTFE-based ceramic-polymer dielectric composites have been widely researched in the communication field due to their good processing, wide range frequency and temperature stability and being able to provide tunable dielectric constant in a scale. In order to improve the compatibility between the ceramic fillers and polymer matrix without damage of dielectric properties, surface modifiers with less carbon remain are preferred. In this paper, tetraethylorthosilicate (TEOS) is employed as a surface modifier to improve the compatibility between the (Ca, Li, Sm)TiO₃ (CLST) ceramic and PTFE, and the dispersion of the ceramic particles in the matrix. FTIR, XPS and TEM results indicate that TEOS is coated on the ceramic particles successfully and forms a silica coating layer. The surface modification improves the dispersion of particles in PTFE and interface contact between the ceramic fillers and PTFE matrix. These improve the thermal stability and reduce the dielectric loss of the dielectric composites. The CLST/PTFE composite modified by TEOS exhibits a dielectric constant of 6.22 with dielectric loss just 0.0012 at microwave frequencies (around 10 GHz).