Bi3NbZrO9掺杂对BST电容器陶瓷介电性能的影响

采用传统固相烧结法,利用X-射线衍射仪(XRD)、扫描电镜(SEM)等方法系统研究了Bi3NbZrO9掺杂量对(Ba,Sr) TiO3(barium strontium titanate,BST)基电容器陶瓷介电性能和微观结构的影响.结果表明:Bi3NbZrO9掺杂没有改变BST陶瓷主晶相,随着掺杂量的增加会出现一些杂相.Bi3NbZrO9掺杂BST陶瓷具有小的介质损耗值,对材料居里峰的移动和展宽效应明显.Bi3NbZrO9掺杂量为lwt％时,烧结温度为1280℃,BST陶瓷具有较佳的介电性能:介电常数(εr) =2325,介质损耗(tanδ)=0.0048,耐压强度(Eb) =7.8 kV/mm(AC),-30 ～ 85℃温度范围内,容温变化率(△C/C)为-12.9％～ 14.3％.     

CaTiSiO5掺杂对钛酸钡锶陶瓷介电性能的影响

采用传统固相烧结法,利用X-射线衍射仪(XRD)、扫描电镜(SEM)等方法系统研究了CaTiSiO5掺杂量对(Ba,Sr) TiO3(barium strontium titanate,BST)基电容器陶瓷介电性能和微观结构的影响.结果表明:CaTiSiO5掺杂的BST陶瓷材料的介电损耗都比较小,但是对材料居里峰的移动和展宽效应都明显.随着CaTiSiO5掺杂量的增加,BST陶瓷的介电常数(εr)先增大然后减小,介电损耗(tanδ)先增大然后减小,变化不大,交流耐压强度(Eb)先增大然后减小,容温变化率先减小然后增大.当掺杂CaTiSiO5质量分数为0.8％时,BST陶瓷的综合介电性能较好:介电常数(εr)=2540,介电损耗(tanδ)=0.0036,耐压强度(Eb)=5.6 kV/mm(AC),在-30～85℃温度范围内,容温变化率为-18.9％ ～ 20.6％,容温特性符合Y5S特性.     

Bi4B2O9对(Ca0.2Sr0.05Li0.375Sm0.375</sub>TiO3陶瓷烧结和微波介电性能的影响

采用传统固相法制备(Ca0.2Sr0.05Li0.375Sm0.375)TiO3钙钛矿微波介质陶瓷,研究了Bi4B2O9对(Ca0.2Sr0.05Li0.375Sm0.375)TiO3陶瓷微波介电性能的影响,利用X射线衍射仪、扫瞄电子显微镜和矢量网络分析仪对其晶体结构、显微组织和微波介电性能进行了研究。结果表明:掺10%Bi4B2O9的(Ca0.2Sr0.05Li0.375Sm0.375)TiO3陶瓷,其烧结温度由1 300℃降至1 080℃。当添加3.5%Bi4B2O9时,其最佳烧结温度为1 150℃,陶瓷的微波介电性能最佳(相对介电常数εr=116.9;品质因数Q×f=3 500GHz;频率温度系数τf=1.2×10-6/℃)。     

Bi_4B_2O_9对(Ca_(0.2)Sr_(0.05)Li_(0.375)Sm_(0.375_)TiO_3陶瓷烧结和微波介电性能的影响

采用传统固相法制备(Ca0.2Sr0.05Li0.375Sm0.375)TiO3钙钛矿微波介质陶瓷,研究了Bi4B2O9对(Ca0.2Sr0.05Li0.375Sm0.375)TiO3陶瓷微波介电性能的影响,利用X射线衍射仪、扫瞄电子显微镜和矢量网络分析仪对其晶体结构、显微组织和微波介电性能进行了研究。结果表明:掺10%Bi4B2O9的(Ca0.2Sr0.05Li0.375Sm0.375)TiO3陶瓷,其烧结温度由1 300℃降至1 080℃。当添加3.5%Bi4B2O9时,其最佳烧结温度为1 150℃,陶瓷的微波介电性能最佳(相对介电常数εr=116.9;品质因数Q×f=3 500GHz;频率温度系数τf=1.2×10-6/℃)。     

低损耗高压陶瓷电容器材料的研究Ⅱ——材料的介电性能

本对Sr-Ti-Bi系高压陶瓷电容器材料的介电性能进行了研究分析。结果表明在Sr-Ti-Bi系中加入一定量的添加剂，可以有效地提高高压陶瓷电容器材料的介电性能。获得了介电性能为：εr=2350;Eb=8.6KV/mm；tgδ=4×10^-4;ΔC/C（-25～ 85≤±11％；绝缘电阻R＝1．2×10^13Ω的介质陶瓷材料。     

电致发光用高介低损耗钛酸锶陶瓷基片的制备

本文研究了用于电致发光用SrTiO3陶瓷基片的制备。考察了在SrTiO3-Bi2O3.xTiO2-系中Bi2O3.xTiO2的加入量以及添加剂CaTiO3、MgTiO3对材料介电性能的影响,在1250℃下烧成得到介电常数rε≈11864～12429、电损耗tgδ≈15×10-4的可用于电致发光器件的陶瓷基片。     

中温烧结(Ba、Sr)TiO3电容器陶瓷

采用常规电容器陶瓷制备工艺 ,借助正交设计实验法研究了在配方对中温烧结 (12 0 0℃ ) (Ba,Sr)TiO3 (BST)基陶瓷介电性能的影响 ,得到了影响BST基陶瓷介电性能的主次因素以及各因素水平影响其性能的趋势 ,同时得到介电常数最大的配方和介质损耗最小的配方 ,得到了综合性能最佳的适合单片电容器和独石电容器的中温烧结 (12 0 0℃ )BST基陶瓷基方 ,它具有中介 (ε≥ 2 195 )、低损耗 (tanδ≤ 0 .0 15 5 )和高耐压 (大于 4 .5Mv/m)。探讨了各组分对BST基陶瓷介电性能的影响机理 ,为研制中温烧结单片电容器和独石电容器陶瓷提供了依据     

掺杂氧化铌对钛酸锶钡铁电陶瓷材料显微结构和介电性能的影响

钛酸锶钡(barium strontium titanate,BST)铁电陶瓷材料的介电常数(ε)随外加直流电场的变化呈现非线性特性.纯BST材料由于较高的ε和较大的介电损耗(tanδ)不能满足移相器介质材料的要求.通过在BST中添加氧化铌(Nb2O5)来改善BST铁电陶瓷材料的介电性能.结果表明:在BST体系中微量掺杂Nb2O5,Nb5 以取代Ti4 的方式存在于钙钛矿的晶格中,形成均匀的固溶体Ba0.5Sr0.5Ti1-xNbxO3.随Nb5 添加量的增加,Curie峰逐渐变宽,峰高逐渐降低,相变弥散效应增强.Nb5 的掺杂能显著降低并稳定BST陶瓷的tanδ,改善BST体系的介电性能.     

添加Sb_2O_5,ZnO和玻璃对(Zr_(0.7)Sn_(0.3))Ti_4陶瓷高频介电性能的影响

用氧化物混合方法制备了主晶相为 (Zr0 .7Sn0 .3)TiO4的高频陶瓷材料。添加Sb2 O5,ZnO和玻璃有效降低了陶瓷的烧成温度和介质损耗。添加 0 .5 %Sb2 O5(摩尔分数 ) ,1.5 %ZnO(质量分数 )和 3.0 %玻璃 (质量分数 )的陶瓷组成在 115 0℃烧结 ,在测试频率 1MHz下的介电性能为 :介电常数ε≈ 38,损耗角正切tanδ=0 .6× 10 - 4 ,介电常数温度系数αε=0± 30× 10 - 6 /℃ ,体电阻率 ρv≥ 10 1 3Ω·cm。用此种陶瓷材料可在中温烧结制成多层陶瓷电容器 (multilayerceramiccapacitor,MLCC)     

CeO2掺杂(Ba,Sr,Ca) TiO3 基高压电容陶瓷的研究

采用固相烧结法合成0.97(Ba0.6Sr0.3Ca0.1)TiO3·0.03(Bi2O3·3TiO2)陶瓷材料,研究了掺杂稀土氧化物CeO2对陶瓷材料介电性能的影响.随CeO2加入量的增加,材料的介电常数先增大后减小再增大后减小,而介电损耗先减小后增大,击穿场强先增大后减小.当CeO2为0.1wt%时,介电常数最大,εr=2384.当CeO2为0.2 wt%时,获得了介电常数为1730,介电损耗为0.0060,耐压为13.125 kV/mm的高压低损耗陶瓷电容器瓷料.利用SEM分析了不同CeO2加入量时样品的断面形貌,结果表明:CeO2可以抑制晶粒生长,细化晶粒,形成固溶体,而过量的CeO2偏析于晶界.     

Effects of Excess Barium Ions on Aqueous Barium Titanate Tape Properties

The effects of excess free barium ions in aqueous barium titanate slip on the resulting BaTiO₃ tape properties were investigated in terms of the slip behavior, green/sintered tape density and morphology, and dielectric properties. The excess free barium ions expressed by means of the Ba/Ti ratio adversely affected most tape properties. Increase in the slip viscosity, green porosity, and agglomeration along with a decrease in mechanical properties and green/sintered density were found with the increase in the Ba/Ti ratio. However, dielectric permittivity was increased with increase in the Ba/Ti ratio. An effort was made to correlate these phenomena with Ba²⁺ leaching in water for realistic multilayer ceramic capacitor applications.     

固相合成微波介电陶瓷Ba2La2Ti2NbO12及介电特性研究

通过固相反应法合成了类钙钛矿结构新铌酸盐Ba2La2Ti2NbO12。分别采用X射线衍射分析、扫描电镜进行了结构分析,并进行了介电性能测试。结果表明：Ba2La2Ti2NbO12室温时为六方层状类钙钛矿结构,有优异的介电性能。晶胞常数为：a=b=5．6726（3）A,c=27．740（2）A,V=773．04（9）A3,Z=3,陶瓷体具有高的介电常数42．7,较高的品质因子31,130GHz,介电常数温度系数-4．2ppm°C-1。     

镁掺杂钛酸钡陶瓷的固相法制备及介电性能

采用固相法分别于1195,1210,1225,1240℃和1255℃下制备了不同掺镁量的Ba(1–x)MgxTiO3(x=0.03,0.06,0.09,0.12)陶瓷。借助X射线衍射和阻抗分析仪对其相结构和介电性能进行了测试。结果表明:随着Mg含量的增加,Ba(1–x)MgxTiO3陶瓷的立方相含量增加,四方相含量减小,介电常数减小,Curie温度降低,Curie峰明显展宽,出现明显的弥散现象。1225℃烧结的Ba0.97Mg0.03TiO3陶瓷的性能稳定,其介电常数和介电损耗分别为1600和0.002。     

中温烧结PSBN系统铁电陶瓷结构和性能的研究

本文研究了中温烧结PbO-SrO-BaO-Nb2O5(PSBN)系统铁电陶瓷介电性能.通过XRD分析确定了主晶相为具有钨青铜结构的Pb0.7Ba0.3Nb2O6(PBN)、Ba0.27Sr0.75Nb2O5.78(BSN);分析了添加剂MnCO3、TiO2、Fe2O3、(MgCO3)4.Mg(OH)2.5H2O对PSBN系统铁电陶瓷介电性能的影响.由于这些添加剂的作用使该系统铁电陶瓷介电系数提高,居里区拓宽并向低温方向移动,绝缘电阻提高,损耗降低,制得高介(ε=4300±200)X7R瓷料.     

超声压电马达用陶瓷材料的研究

研究了钡锶锑锰等离子掺杂对锆钛酸铅(PZT)系压电陶瓷的介电、压电性能和体积密度的影响。实验结果表明:对于Pb0.95Ba0.03Sr0.02(Zr1-yTiy)O3+xwt%MnSb2O6(PBSZTMS),在x=1.5、Zr/Ti=52/48附近获得了优越的压电活性。对于Pb0.95Ba0.03Sr0.02(MnSb2O6)x/3(Zr54Ti46)1-xO3(PBSMSZT),综合性能较好的组成点出现在x=0.05处。对于PbaBabSrc(MnSb2O6)x/3(Zr1-yTiy)1-xO3+zwt%MnSb2O6系列配方,发现Sr2+和Ba2+的共同添加会使样品致密度降低,介电常数、介质损耗和压电常数增加;当a=1,b=0,c=0,x=0.03,y=0.48,z=0.76时,获得了综合性能较好的陶瓷材料,有望应用于大功率超声压电马达器件领域。     

机械球磨时间对液相烧结Ba2Ti3Nb4O18陶瓷材料结构和性能的影响

Ba2Ti3Nb4O18是BaO-TiO2-Nb2O5体系中一种新型的介质材料,具有优良的微波介电性能.为满足低温共烧陶瓷技术(low temperature cofired ceramics,LTCC)对微波介质陶瓷材料的低温烧结要求,实现在900℃与银电极共烧,添加了质量分数为5%的ZnO-B2O3玻璃作助融剂,并研究了机械球磨时间对粉料粒径、陶瓷样品的烧结密度、显微结构和介电性能的影响.机械球磨6h的粉体粒径适中(约90nm),用该粉料制备的陶瓷样品可以在900℃致密烧结(大于理论密度的95%).且高频介电性能为(1MHz下测试):介电常数εt≈36,介电损耗tanδ≈2× 10-4,电容温度系数αc≈2.5×10-6/℃.同时微波介电性能良好:εt=33.3,品质因数和频率的乘积Qf=14274GHz.可与银电极共烧结作为LTCC介质瓷料.     

Improvement in the Microstructures and Dielectric Properties of Barium Strontium Titanate Glass–Ceramics by AlF3/MnO2 Addition

The microstructures and dielectric properties of barium strontium titanate glass–ceramics are closely related to the AlF₃ and MnO₂ additions. The grain morphology was changed by adding AlF₃, while the dielectric loss was decreased significantly by adding MnO₂. At the same time the breakdown strength (BDS) was improved by doping 4 mol% AlF₃ and 1 mol% MnO₂ with the glass–ceramics. The present investigation resulted in the development of glass–ceramic compositions with high dielectric BDS and low dielectric loss for high energy density capacitor applications.     

铁电薄膜的材料系统与功能性质

集成铁电体把铁电材料与集成半导体技术联合起来,以发展出一批新的电子器件.铁电薄膜在其中发挥着非挥发性记忆、热释电、压电、光折变、抗辐射、声学的和/或介电的功能性质.在不同的器件应用中,铁电薄膜的材料体系是不相同的.在非挥发性存贮器(NVRAM)中,PZT薄膜面临着SrBi2Ta2O9(SBT)系列铁电体的强力挑战;Ba1-xSrxTiO3(BST)则可能出现在下一代高密度动态随机存贮器(DRAM)中.金属氧化物电极和/或过渡层可以克服Pt电极面临的一些问题,并有助于铁电薄膜的外延生长.     

Measurements of dielectric constant and quality factor of Ba(Mg1/3Ta2/3)O3 at X band frequencies

Dielectric properties of Ba(Mg_1/3Ta_2/3)O₃ in forms of ceramic, single crystal fiber, and polyethylene composite at microwave frequencies were measured. The dielectric constants 23.33, 24.30, and 26.50 and the quality factors 8,050, 6,430, and larger than 2,000 at 10 GHz were measured for the ceramic, hot pressed ceramic and the fiber respectively. The powder was studied by forming composites of Ba(Mg_1/3Ta_2/3)O₃ -Polyethylene. It is found that the experimental dielectric constant values at X band frequencies fit reasonably well to the logarithmic mixture rule. A newly reported mixing equation by Wakino et al. was studied by comparing with our experimental results.     

The Effect of Dopants on the Dielectric Properties of Ba(B'1/2Ta1/2)O3 (B'=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb, and In) Microwave Ceramics

Low-loss dielectric ceramics based on Ba(B'_1/2Ta_1/2)O₃ (B'=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb, and In) complex perovskites have been prepared by the solid-state ceramic route. The dielectric properties (ɛ_r, Q _u, and τ_f) of the ceramics have been measured in the frequency range 4–6 GHz by the resonance method. The resonators have a relatively high dielectric constant and high quality factor. Most of the compounds have a low coefficient of temperature variation of the resonant frequencies. The microwave dielectric properties have been improved by the addition of dopants and by solid solution formation. The solid solution Ba[(Y_{1− x} Pr _x )_1/2Ta_1/2]O₃ has x =0.15, with ɛ_r=33.2, Q _u× f =51,500 GHz, and τ_f≈0. The microwave dielectric properties of Ba(B'_1/2Ta_1/2)O₃ ceramics are found to depend on the tolerance factor ( t ), ionic radius, and ionization energy.