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BST陶瓷制备及介电性能研究 总被引:1,自引:1,他引:1
采用微波水热法合成了纳米晶钛酸锶钡(Ba0.6Sr0.4TiO3,简称BST)粉体,并将粉体烧结成陶瓷,对样品的介电性能进行了测试,研究分析了材料的介电性能,并与传统制备工艺获得的样品进行了性能上的对比,实验结果表明:微波水热法获得的BST粉体较细,其合成温度和烧结成瓷温度较传统制备工艺大幅降低,分别为195℃和1 230℃,可以获得晶粒尺寸在3μm以下的陶瓷。随着晶粒的减小,BST陶瓷的相对介电常数和介电损耗降低,尤其是介电损耗因子有较大幅度降低。 相似文献
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采用溶胶-凝胶法制备出包裹MgO粉体的BST凝胶,凝胶经干燥、预烧后得到BST/MgO粉体.DTA/TGA、XRD和EDS分析以及SEM和TEM观察表明,BST在650 ℃晶化基本完成,1 300℃烧结体的晶粒均匀,气孔呈圆形.确定出BST凝胶预烧温度为700℃,BST/MgO陶瓷的烧结温度为1 300℃.在1 300℃烧结后,等静压试样的相对密度达到92.4%,径向收缩率为18.1%,轴向收缩率为18.4%.BST/MgO陶瓷中只包含BST和MgO两相.介电性能检测表明,在8~12 GHz范围内介电常数降至50以下,损耗角正切达10-2数量级. 相似文献
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微波烧结Ba_(6-3x)Sm_(8+2x)Ti_(18)O_(54)陶瓷材料的初步研究 总被引:1,自引:0,他引:1
研究了Ba_(6-3x)Sm_(8+2x)Ti_(18)O_(54)(x=0.67,BST)陶瓷材料的微波烧结情况,从烧结特性、微结构与相组成及微波介电性能等方面对微波烧结的样品与传统工艺制得的样品进行了对比.结果表明, 与传统制备工艺相比,微波烧结BST陶瓷缩短了烧结周期,并促进了样品的致密化,其物相组成和传统烧结的样品没有区别,且晶粒细小分布均匀.微波烧结BST陶瓷可获得较优的微波介电性能:介电常数ε_r=82.89,品质因数与频率之积Qf=8 450 GHz(频率f=4.75 GHz),谐振频率温度系数τ_f=22.58×10~(-6)/℃. 相似文献
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采用溶胶-凝胶工艺制备了(Ba,Sr)TiO3凝胶,并利用微波烧结技术对粉体进行了合成和烧结,获得了晶粒尺寸在1μm以内的Ba0.65Sr0.35TiO3热释电陶瓷。对样品的介电特性和热释电特性进行了测试,分析了微波烧结工艺对材料电性能的影响。实验结果表明:该工艺可将钙钛矿相的合成温度由1100℃降低至900℃,并在1310℃烧结25min获得细晶粒的Ba0.65Sr0.35TiO3,其热释电系数和介电常数与传统陶瓷相差不大,从而材料的热释电响应优值因子要比传统方法获得的样品提高了近1倍。 相似文献
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采用凝胶注模工艺制备了Ce0.9Gd0.1O2-δ(GDC)粉体,对其性能进行了TG-DSC、XRD、TEM和粒度等表征,分别与同等原料采用传统固相合成工艺制备的粉体,与不同原料同种凝胶注模工艺制备的粉体进行了性能比较。采用不同压力成型了坯体,在1350℃烧结得到瓷体,对粉体的烧结性能和瓷体的电导性能进行了表征。结果表明:采用凝胶注模工艺在600℃就能获得纯相GDC粉体,比固相反应合成GDC粉体温度降低400℃;相比以氧化物为原料合成的粉体,以硝酸盐为原料采用凝胶注模工艺合成的粉体有助于氧化钆在氧化铈晶格中的固溶;在1350℃烧结获得相对密度为96.5%瓷体,600℃电导率为0.0258S/cm,满足中温电解质材料对电导率的要求。 相似文献
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Pechini法制备超细BST粉体及其陶瓷的研究 总被引:1,自引:0,他引:1
采用Pechini法制备了约100nm的(Ba0.79Sr0.21)TiO3超细粉体,并在其中掺杂超细Bi4Ti3O12粉体制备了BST混合粉体.并用其制备了平均粒径为0.5μm、ετ为1740和tanδ为0.0038的BST陶瓷.研究了热处理温度和分散剂的量对粉体性能的影响,烧结温度对BST陶瓷介电性能和显微结构的影响。得到了较优的工艺参数,即热处理温度800℃、分散剂的量2.25mL和烧结温度1150℃. 相似文献
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《电子元件与材料》2017,(12):11-15
采用溶胶-凝胶法制备了非晶SiO_2粉体,并研究了不同溶液配比对所得粉体粒度和分散性的影响。结果表明:当H2O和TEOS摩尔比为20:1和40:1时,可以制备出分散性较好的非晶SiO_2粉体,其粒度分别为700 nm和120 nm。在此基础上,研究了不同原料粉体对SiO_2材料烧结特性和微波介电性能的影响规律。研究发现:粉体粒度较小,有利于降低SiO_2材料的烧结温度,提高其相对密度,抑制其析晶现象。当烧结温度为1050~1200℃时,SiO_2材料的相对介电常数为2.50~3.75,Q·f值为9850~61 272 GHz,τf值的变化范围为±15×10–6/℃(温度范围为25~85℃),适合用于制作微波介质基板。 相似文献
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纳米粉体对低温烧结CMS微波介质陶瓷的改性 总被引:2,自引:1,他引:1
在低温烧结的CaO-MgO-SiO2(CMS)陶瓷中,引入粒径为50~100nm的Ca0.7Mg0.3SiO3纳米粉体,研究了纳米粉体对陶瓷烧结行为和介电性能的影响。研究发现:添加质量分数为5%的纳米粉体能有效促进陶瓷的烧结,拓宽其烧结温度范围,提高其微波介电性能。在890℃烧结后得到良好的介电性能:εr=9.31,Q·f=22574GHz。通过对电镀前后性能的对比发现,添加适量纳米粉体,可消除陶瓷中的大气孔,有效防止电镀过程中电镀液渗入陶瓷体,从而大大改善电镀后陶瓷的介电性能。 相似文献
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《Materials Science in Semiconductor Processing》2002,5(2-3):215-221
Ferroelectric films based on barium strontium titanates have been widely investigated in microwave devices, such as tunable filters and phase shifters. Recent trends include integration of ferroelectric layers into multilayer dielectric modules by a tape casting procedure. The sintering temperature of BST prepared by the conventional oxide mixing method is, however, very high (1350°C), and only platinum or refractory metals can be used for conductors and electrodes in the co-sintering process of tapes. Decrease of the sintering temperature of BST below 1000°C would result in good compatibility of the ferroelectric layers with embedded electrodes made of highly conductive metals, such as silver. The effects of B2O3 addition and powder properties on the sintering behavior and the dielectric properties were investigated. The sol–gel method was used to prepare all powders because of its high purity and homogeneity control and its ability to produce fine powders. The BET results showed that all powders had high specific surface areas, but in dilatometric studies, only boron addition produced the desired shrinkage and dense microstructure at low temperatures (<1000°C). This was also verified in sintered microstructures. The XRD showed an appearing of two secondary phases caused by boron addition. This decreased permittivity and thus set a limit on boron addition. 相似文献
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The dielectric and microwave properties of Ba0.6Sr0.4TiO3 (BST60) thin films with a MgO buffer layer deposited on Al2O3 substrates were investigated. Insertion of the MgO buffer layer is demonstrated to be an effective approach to fabricate low-dielectric-loss BST thin films. x-Ray pattern analysis indicates that the thin films exhibit good crystalline quality with a pure perovskite phase and that insertion of the MgO buffer layer does not change the crystal structure of BST. The nonlinear dielectric properties of the BST films were measured by using an interdigital capacitor (IDC). At room temperature, the tunability of the BST films with a MgO buffer layer was 24.1% at a frequency of 1 MHz with an applied electric field of 80 kV/cm. The dielectric loss of the BST thin films is only 0.005 to 0.007 in the frequency range from 20 Hz to 2 MHz, the same as for BST films prepared on single-crystal MgO substrates. The microwave dielectric properties of the BST thin films were also measured by a vector network analyzer from 50 MHz to 10 GHz. 相似文献
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采用普通固相反应法制备了0.45Ba0.55Sr0.45TiO3-0.55MgO-Mn(NO3)2/MnCO3(简称BST-MgO)陶瓷,通过XRD和SEM研究了不同形态含锰化合物(固态MnCO3及液态Mn(NO3)2)掺杂对所制BST-MgO陶瓷致密化及微波介电性能的影响。结果表明,液态Mn(NO3)2掺杂可以增加锰离子进入BST晶格的几率,同时抑制镁离子进入BST晶格,提高BST-MgO陶瓷的致密度,降低介质损耗,获得较高的综合性能:10 kHz下r=116,tan=0.003 8,可调率(Tu)为19.64%,优值K=51.68;3 GHz时Q.f值达788 GHz。 相似文献