二步法合成低温烧结（MQ，Zn）TiO3介电陶瓷

首先采用固相法合成了（Mg，Zn）2TiO4粉体，然后将钛酸丁酯水解制备出TiO2溶胶，再利用TiO2溶胶对已合成的（Mg，Zn）2TiO4粉体进行包覆。包覆后的粉体经500℃预烧后在1150℃烧结成瓷，采用XRD、SEM分别做了样品的物相和显微结构分析，测试结果表明：当TiO2，（Mg，Zn）2TiO4为1．1时，合成产物为纯的（Mg，Zn）TiO3相。在1MHz下测试了样品的介电性能，结果表明：当TiO2／（Mg，Zn）2TiO4为1．1，烧结温度为1150℃时，陶瓷介电性能最好。     

烧结温度对Bi2(Mg1/3Nb2/3)2O7介电陶瓷性能的影响

采用传统固相反应法制备了Bi2(Mg1/3Nb2/3)2O7(β-BMN)介电陶瓷,借助X射线衍射(XRD)研究了不同预烧温度合成β-BMN粉体的物相组成,借助扫描电镜(SEM)研究了不同烧结温度β-BMN的显微结构,考察了不同烧结温度和保温时间对β-BMN陶瓷性能的影响.结果表明:合成温度为850℃时已经完全形成主晶相(β-BMN).随着烧结温度的增加,样品的介质损耗(tanδ)先变小后增大,而相对介电常数(εr)先增大后减小.当烧结温度为1000℃保温5h时,得到的陶瓷的综合性能较佳:ρ=7.69g/cm3,εr=207,tanδ=0.00197.     

BaTi4O9介电陶瓷的低温烧结

研究液相多元添加对BaTi4O9介质陶瓷的烧结和介电性能的影响.通过添加(CuO和V2O5)烧结助剂来达到降低烧结温度的效果,并且使其保持较好的高频性能.实验结果表明在添加合适的烧结助剂下,烧结温度为1180℃时,BaTi4O9介电陶瓷在1MHz下的介电性能:ε=41.2,tan δ=5,τ=82 ppm/℃.基本保持了良好的介电性能.     

低温烧结(Zn0.65Mg0.35)TiO3-CaTiO3介电陶瓷的研究

本文对(Zn0.65Mg0.35)TiO3-CaTiO3(ZMT-CT)系统的微观结构和介电性能进行了研究.研究结果表明,通过添加一定量H3BO3-ZnO-BaCO3(BZB)玻璃能够促进晶粒生长,有效降低烧结温度.同时,调节(Zn0.65Mg0.35)TiO3和CaTiO3比例可以获得温度系数在零附近的瓷料.当加入6.5wt%BZB时瓷料可以在900℃烧结,ε=21～22,αε＜±30 ppm/℃,tanδ=1.3×10-4(1 MHz),是制备LTCC(低温共烧陶瓷电容器)的优秀候选材料,具有很好的应用前景.     

(Ca,Ta)共掺杂TiO2陶瓷巨介电性能及机理

随着社会的飞速发展,微电子器件的功能不断向一体化方向发展,使开发具有高介电常数、低介电损耗、良好频率和温度稳定性的高介电陶瓷受到越来越多的关注.本工作通过固相反应烧结法制备了(Ca,Ta)共掺杂的TiO2陶瓷.采用X射线衍射仪(XRD)、扫描电镜(SEM)及能谱分析仪(EDS)、阻抗分析仪、X射线光电子能谱(XPS)等...     

介电陶瓷材料专利申请的权利要求能否得到说明书支持的判断

介电常数和介电损耗是评判陶瓷材料介电性能的最重要的两个参数,文章从专利申请中介电常数和介电损耗的实验数据出发,探讨了对于涉及介电参数的陶瓷材料的权利要求能否得到说明书支持的判断,并对申请人给出的撰写建议,主要涉及专利法第二十六条第四款关于权利要求能否得到说明书支持的规定。     

(Zn1-xMgx)TiO3微波陶瓷系统介电性能的研究

对 (Zn1-xMgx)TiO3 系统的微观结构和介电性能进行了研究。通过添加一定量的MgO稳定ZnTiO3 六方钛铁矿结构 ,有效抑制了ZnTiO3 分解为Zn2 TiO4 和TiO2 。同时 ,通过调整x值 (x =0 .1～ 0 .4) ,可以获得介电性能优良的微波瓷料。当x=0 .3～ 0 .3 5时 ,在 10 6 0℃烧结 ,其品质因数Q0 >2 0 0 0 0 ( 6 .5GHz) ,谐振频率温度系数τf≈ 2× 10 - 6 /℃ ,介电常数ε =18～ 2 2。通过研究发现热处理可以改变系统微观形貌 ,其品质因数Q0 与热处理温度关系密切 ,当保温时间均为 2h时 ,随着热处理温度的升高 ,Q0 从 2 3 83 3 .93相应升高到 475 84.0 0。     

(Mg1-xCox)TiO3基微波陶瓷介电性能研究

以MgO,Co2O3和TiO2为原料,用固相反应法制备了(Mg1-xCox)TiO3(MCT)系陶瓷.研究了CoTiO3含量对其微观结构和微波介电性能的影响.结果表明:添加适量的CoTiO3,可以适当降低烧结温度,调整烧结温度范围.当掺入量为10 mol%,烧结温度为1350 ℃时,MCT陶瓷具有优良微波介电性能:εr=18.99;Q×f=154000 GHz,τf=-45 ppm/℃.     

掺杂ZnO-B2O3低温烧结BiNbO4介质陶瓷的研究

研究了烧结助剂ZnO-B2O3对BiNbO4陶瓷烧结特性及介电性能的影响.结果表明ZnO-B2O3形成晶界玻璃相存在于晶粒之间,促进烧结,大幅度降低BiNbO4陶瓷的烧结温度,促使瓷体晶粒尺寸均匀和致密;但ZB的质量分数大于3%,阻碍晶粒长大,破坏晶体结构和排列,导致材料的缺陷和本征损耗增加,从而降低材料的介电性能.ZnO-B2O3的掺杂量以1%为最佳,在880℃保温4h,可达到97%理论密度,在100MHz测试频率下,εr=42,tanδ＜1.5×10-3.     

多孔低介电氧化硅陶瓷材料的制备

采用氧化硅为原料,木屑作为造孔剂制备了多孔的氧化硅陶瓷材料。借助于气孔率测试、抗弯强度测试、介电性能测试和SEM测试手段分析了造孔剂和烧结助剂的添加量对材料性能的影响。结果表明:加入BN作为添加剂烧成的氧化硅抗弯强度最大可达到14.80MPa。加入木屑作为造孔剂制备的陶瓷可以形成明显的气孔,气孔率最高可达到48.40%,介电常数最低可以达到3.0。     

Low-Fired (Zn,Mg)TiO3 Microwave Dielectrics

A dielectric ceramic comprised of (Zn_{1- x} Mg _x )TiO₃ ( x = 0 to x = 0.5) with low sintering temperature and promising microwave properties was prepared by applying a semichemical synthesis route and a microbeads milling technique. X-ray diffractometry and thermal analyses results indicated that the phase stability region of the hexagonal (Zn,Mg)TiO₃ extended to higher temperatures as the amount of magnesium increased. The dielectric properties in this system exhibited a significant dependence on the sintering conditions, especially near the phase decomposition temperature. From 950°C, the temperature compensation characteristics occurred as the phase composition changed from hexagonal (Zn,Mg)TiO₃ to two phases: (Zn,Mg)₂TiO₄ and rutile. The magnesium content for zero temperature coefficient (tau_f) was ~3 mol% at 950°C; however, tau_f increased with the sintering temperatures because of the shift of the decomposition temperature.     

Dielectric properties and relaxor behavior of 0.935(Na0.5Bi0.5)TiO3-0.065BaTiO3 lead free piezoelectric ceramic

Dielectric properties of 0.935(Na_0.5Bi_0.5)TiO₃-0.065BaTiO₃ lead free piezoelectric ceramic are studied. The study shows a diffuse phase transition (DPT) characterized by a frequency dispersion of permittivity which is related to cation disorder at A-site. Additionally to this dispersion, this solid solution exhibits relaxor behavior. The mechanism of relaxor behavior was discussed according to Debye, Vogel–Fulcher (V–F) and Power law models and the suitable model was predicted by means of goodness of parameter.     

(1-x)Ca_(15/16)Sr_(1/16)TiO_3-xLi_(1/2)Nd_(1/2)TiO_3陶瓷的相组成、显微结构及微波介电性能

采用传统固相法合成了(1-x)Ca_(15/16)Sr_(1/16)TiO_3-xLi_(1/2)Nd_(1/2)TiO_3(CST-LNT)系列微波介质陶瓷材料,研究了该系列材料的物相组成、显微结构及微波介电性能。XRD分析结果表明所有样品均为钙钛矿结构,无二次相出现。随着Li_(1/2)Nd_(1/2)TiO_3的加入,陶瓷平均晶粒尺寸下降,表明Li_(1/2)Nd_(1/2)TiO_3会抑制晶粒生长。随着x的增加,介电常数下降,频率温度系数向负方向移动。当x=0.85时,1250℃保温4 h可以得到优良的微波介电性能:ε_r=125.4,Q×f=2230GHz,τ_f=+14.4 ppm/℃。     

固态反应法制备CaCu3-xMgxTi4O12陶瓷的介电性能研究

利用固态反应法制备了CaCu3-xMgxTi4O12（x=0,0．2,0．4,0．6,0．8,1．0）陶瓷,并分析探讨了MgO添加量对其介电性能的影响。研究结果表明,添加MgO后陶瓷晶粒有变小的现象,且MgO的添加摩尔比为0．6时其介电常数最佳,但介电常数随频率增加下降也较快;MgO添的加摩尔比为0．2和0．4时虽然介电常数增加较少,但随频率变化幅度却较小。在频率〈1000Hz时添加MgO会使陶瓷使的介电损耗大幅上升,这表明添加MgO有降低电阻的效果。     

固态反应法制备CaCu3-xMgxTi4O12陶瓷的介电性能研究

利用固态反应法制备了CaCu3-xMgxTi4O12(x=0,0.2,0.4,0.6,0.8,1.0)陶瓷,并分析探讨了MgO添加量对其介电性能的影响.研究结果表明,添加MgO后陶瓷晶粒有变小的现象,且MgO的添加摩尔比为0.6时其介电常数最佳,但介电常数随频率增加下降也较快;MgO添的加摩尔比为0.2和0.4时虽然介电常数增加较少,但随频率变化幅度却较小.在频率＜1 000 Hz时添加MgO会使陶瓷使的介电损耗大幅上升,这表明添加MgO有降低电阻的效果.     

Colossal permittivity of (Gd + Nb) co-doped TiO2 ceramics induced by interface effects and defect cluster

Material with high dielectric constant plays an important role in energy storage elements. (Gd + Nb) co-doped TiO₂ (GNTO) ceramics with giant dielectric permittivity (>10⁴), low dielectric loss, good temperature and frequency stability in broad range of 30–150 °C and 10²–10⁶ Hz have been systematically characterized. Especially, a low dielectric loss of 0.027 and a giant dielectric permittivity of 5.63 × 10⁴ at 1 kHz are attained for the composition with x = 0.01. Results of complex impedance spectroscopy, I–V curve and frequency dependent dielectric constant under DC bias indicate that internal barrier layer capacitance (IBLC) effect, electrode effect and electron-pinned defect-dipole (EPDD) effect contribute to the colossal permittivity (CP) property simultaneously.     

Dielectric dispersion near the morphotropic phase boundary of 0.64PMN-0.36PT ceramics

A near morphotropic phase boundary (MPB) composition of PMN-PT ceramic, 0.64Pb(Mg_1/3Nb_2/3)O₃-0.36PbTiO₃, has been synthesized for various piezoelectric, ferroelectric and dielectric applications. The relaxation mechanisms and dielectric characteristics of this solid solution have been investigated with dielectric spectroscopy measurements in the frequency range of 20 Hz–2 MHz. The dielectric properties have shown distinct and prominent Debye type relaxation at the temperatures corresponding to the ferroelectric phase. The peak in dielectric loss parameter has been found to be dominated by the dc conductivity in paraelectric phase. The experimentally obtained values of various parameters have been found in agreement with the values obtained by fitting of the experimental data in Debye model. An excellent agreement of the results with Debye distribution of relaxation times was obtained with the distribution parameter α showing minima around the ferro-to para-electric phase transition. Different activation energies of the relaxation time have been observed in the ferroelectric and paraelectric phases. An average relaxation time has been found to decrease from ～10^?3 s to ～10^?6 s with the increasing temperatures.