微波反应合成纳米Ba1-xZnxTi1-ySnyO3介电材料及其结构、性能研究

采用微波反应技术,合成了一系列Ba1-xZnxTi1-ySnyO3固溶体纳米粉末（0≤ x≤0.3,0≤y≤0.5),XRD物相分析和d间距一组成图证明,产品为立方晶系的完全 互溶取代固溶体,结果符合Vegard定律。TEM形貌观察,粒子为均匀球形,平均粒 径40nm。通过制陶实验,分别测定了该系列固溶体的室温介电常数、介电损失以及 介电常数随温度的变化,结果发现,采用化学方法在BaTiO3中掺入适量锌和锡,由 于掺杂离子均匀进入母体晶格,引起tc降低,室温介电常数达12000以上,介电损 耗仅为0.007。纳米粉体的烧结温度为1150℃,比传统微米级粉体的烧结温度降低 200－250℃。     

Ba~1~-~xCa~xSn~yTi~1~-~yO~3纳米材料的、合成结构与性能

采用常压水相法,在100℃以下制备了一系列Ba~1~-~xCa~xSn~yTi~1~-~yO~3固溶体纳米粉末(0≤x≤0.5,0≤y≤0.3),经XRD物相分析和d-间距-组成图证明,产品为立方晶系的完全互溶取代固溶体,结果符合Vegard定律。TEM形貌观察,粒子为均匀球形,平均粒径70nm。通过制陶实验,分别测定了该系列固溶体的室温介电常数以及介电常数随温度的变化,结果发现,用软化学方法在BaTiO~3中掺入适量钙和锡,由于掺杂离子均匀进入母体晶格,引起T~c降低,室温介电常数达9800,经BaTiO~3纯相提高6倍,而介电损失却降低50%。     

Ba~1~-~1~.~5~yLa~ySn~xTi~1~-~xO~3固溶体的合成、结构与性能

用软化学合成方法,在100^oC以下制备了一系列Ba~1~-~1~.~5~yLa~ySn~xTi~1~-~xO~3固溶体纳米粉末,XRD物相分析和d间距-组成图证明,产品为完全互溶取代固溶体.TEM观察,粒子为均匀球形,平均粒径70nm.通过制陶实验,分别测定了该系列固溶体的室温介电常数,结果发现,用化学方法在BaTiO~3中掺入适量锡和镧,引起T~c降低,当x=0.2,y=0.08时,室温介电数高达28000,比BaTiO~3纯相提高20倍.     

BaZrxTi1-xO3·yLa2O3固溶体的合成、结构与性能

在100℃以下用软化学合成方法制备了一系列BaZrxTi1-xO3·yLa2O3O(0≤x≤0.3,0≤y≤0.04)固溶体纳米粉末.XRD物相分析及d-间隔-组成图证明,产品为完全互溶取代固溶体.从TEM谱图观察,粒子为均匀球形,平均粒径60nm.通过制陶实验对该系列固溶体的介电特性进行了测试,结果表明,采用化学掺杂方法在BaTiO3中掺入适量锆和镧后,样品的室温介电常数可提高20倍.     

室温固态反应制备纳米Ba1－xSrxTiO3固溶体及其结构与介电性能研究

采用室温固态反应合成了一系列Ba_1－xSr_xTiO₃固溶体纳米粉末(0≤x≤1.0). 经XRD物相分析和d-间距-组成图证明, 产品为立方晶系的完全互溶取代固溶体. TEM形貌观察, 粒子基本为球形, 平均粒径40 nm. 该方法具有产率高, 无需溶剂, 对环境无污染等优点. 通过制陶实验, 分别测定了该系列固溶体的室温介电常数、介电损失以及介电常数随温度的变化. 结果发现, 采用室温固态反应在BaTiO₃中掺入适量锶, 由于掺杂离子均匀进入母体晶格, 引起居里点降低, 室温介电常数达11000以上, 介电损耗由BaTiO₃纯相的0.03 (3%)降为0.008 (0.8%). 纳米粉体的烧结温度为1180 ℃, 比传统微米级粉体的烧结温度降低100～150 ℃.     

低温固态反应制备纳米Ba_(1-y)Sr_yTi_(1-x)Zr_xO_3介电材料及性能研究

将TiCl4的水解产物与固体Ba(OH)2按摩尔比1∶1混合,混合物经室温研磨、100℃烘干,得到钛酸钡纳米晶;按相同工艺掺杂,合成了一系列Ba1-ySryTi1-xZrxO3(0x≤0.3,0y≤0.4)固溶体;采用X射线衍射分析了产物的晶体结构,采用透射电镜观察了其形貌;并测定了系列固溶体的室温介电常数、介电损失.结果表明,所制备的Ba1-ySryTi1-xZrxO3为完全互溶取代固溶体,由平均粒径70 nm的球形微粒组成.经低温固态反应掺入适量锆、锶后,BaTi O3的室温介电常数由3 000提高到20 000左右.     

Ba1-xSrxTi1-yMyO3固溶体的湿化学法合成与介电特性

为了提高 BaTiO3的室温介电常数和减少介电损失，目前工业上在电子元器件的制造过程中，采用固相掺杂方法，于 BaTiO3粉体中掺入适量锶、锆、锡和一些稀土元素的氧化物，以改善其性能。但由于固相掺杂的不均匀性，使得元器件的各项参数改善并不理想 [1]。近几年国外虽有用 Sol Gel法对 BaTiO3进行掺杂改性的研究 [2]，但却因为原材料价格昂贵而无法在我国生产。为此，本文率先用湿化学合成方法，在 100℃以下水溶液中对 BaTiO3进行了掺杂改性，使掺杂离子均匀进入母体晶格，合成了一系列 BaTiO3基固溶体纳米粉末，并对其介电特性进…     

Ba1-xSrxMyTi1-yO3(M=Zr, Sn)纳米材料的软化学合成、结构与介电特性

用软化学方法,在１００℃以下合成了一系列Ｂａ_(１－ｘ)Ｓｒ_ｘＭ_ｙＴｉ_(１－ｙ)Ｏ_３固溶体纳米粉末（Ｍ＝Ｚｒ,Ｓｎ,０ ≤ｘ≤０．４,０≤ｙ≤０．３）,经ＸＲＤ物相分析和ｄ－间距－组成图证明,产品为立方晶系的完全互溶取代固溶体,结果符合Ｖｅｇａｒｄ定律．ＴＥＭ形貌观察,粒子为均匀球形,平均粒径７０ｎｍ．通过制陶实验,分别测定了该系列固溶体的室温介电常数以及介电常数随温度的变化．结果发现,用软化学方法在ＢａＴｉＯ_３中掺入适量锶和锆或锡,由于掺杂离子均匀进入母体晶格,引起Ｔｃ降低,介电性能改善显著．当ｘ＝０．２,ｙ＝０．１时,室温介电常数达 １１ ０００,比 ＢａＴｉＯ_３纯相提高 ８倍,而介电损失却下降 ３倍．     

室温固态反应制备纳米Ba1－xSrxTiO3固溶体及其结构与介电性能研究

采用室温固态反应合成了一系列Ba_1－xSr_xTiO₃固溶体纳米粉末(0≤x≤1.0). 经XRD物相分析和d-间距-组成图证明, 产品为立方晶系的完全互溶取代固溶体. TEM形貌观察, 粒子基本为球形, 平均粒径40 nm. 该方法具有产率高, 无需溶剂, 对环境无污染等优点. 通过制陶实验, 分别测定了该系列固溶体的室温介电常数、介电损失以及介电常数随温度的变化. 结果发现, 采用室温固态反应在BaTiO₃中掺入适量锶, 由于掺杂离子均匀进入母体晶格, 引起居里点降低, 室温介电常数达11000以上, 介电损耗由BaTiO₃纯相的0.03 (3%)降为0.008 (0.8%). 纳米粉体的烧结温度为1180 ℃, 比传统微米级粉体的烧结温度降低100～150 ℃.     

Pb1-xTbxTi1-xMnxO3(O≤x≤0.10)固溶体的合成、结构与表征

用固相反应合成了Pb1-xTbxTi1-xMnxO3(0≤x≤0.10)固溶体,并用X射线粉末衍射进行了表征,室温下其空间群为P4mm.热分析仪测试结果显示,随着Tb和Mn掺杂量的增加,该固溶体的相变温度Tc降低.介电常数在Tc附近出现峰值,表明对应的相变是铁电相变.磁性测量显示,当x=0.08和x=0.10时,Pb1-xTbxTi1-xMnxO3分别在25和29 K附近有顺磁性向反铁磁性的转变.     

Hydrotherrnal synthesis, structure and property of nano-BaTiO3-based dielectric materials

A series of Ba1-xSrxTi1-yZryO3 (0≤x≤0.5, 0≤y≤0.4) and Ba1-xZnxTi1-ySnyO3 (0≤x≤0.3, 0≤y≤0.3) solid solutions were synthesized by Iow-temperature/Iow-pressure hydrothermal method below 170℃, 0.8 MPa. XRD pattern and cell parameters-composition figures of these prepared powders demonstrated that they are completely miscible solid solutions based on BaTiO3. Furthermore, TEM showed that they have a shape of uniform, substantially spherical particles with an average particle size of 70 nm in diameter. The sintered ceramics of those powders doped by Sr2+ and Zr4+ or Zn2+ and Sn4+ have dielectric constant twelve times higher than and dielectric loss 1/6 those of pure BaTiO3 phase at room temperature.     

Synthesis, structure and dielectric properties of Ba1-xSrx My Ti1-yO3 (M = Zr, Sn)

A series of Ba1-xSrxMyTi1-yO3 (M = Zr, Sn, 0≤x≤0.4, 0≤y≤0.3) solid solutions were synthesized with the soft chemical method below 100 ℃. XRD pattern and cell parameters-composition figures of the prepared powder demonstrate that they are completely miscible solid solutions based on BaTiO3. Furthermore, TEM shows that they have a shape of uniform, substantially spherical particles with an average particle size of 70 nm in diameter. The sintered ceramics of the powder doped with Sr2 and Zr4 or Sn4 have dielectric constant eight times higher and dielectric loss thirty per cent lower than those of pure BaTiO3 phase at room temperature.     

Hydrothermal synthesis, structure and property of nano-BaTiO3-based dielectric materials

A series of Ba_1-xSr_xTi_1-yZr_yO₃ (0≤x≤0.5, 0≤y≤0.4) and BA_1?xZn_xTi_1?ySn_yO₃ (0≤x≤0.3, 0≤y≤0.3) solid solutions were synthesized by low-temperature/low-pressure hydrothermal method below 170°C, 0.8 MPa. XRD pattern and cell parameters-composition figures of these prepared powders demonstrated that they are completely miscible solid solutions based on BaTiO₃. Furthermore, TEM showed that they have a shape of uniform, substantially spherical particles with an average particle size of 70 nm in diameter. The sintered ceramics of those powders doped by Sr²⁺ and Zr⁴⁺ or Zn²⁺ and Sn⁴⁺ have dielectric constant twelve times higher than and dielectric loss 1/6 those of pure BaTiO₃ phase at room temperature.     

溶胶-凝胶法制备掺锰钛酸钡纳米粉体及其陶瓷

The Mn-doped barium titanate nanosized powders and ceramics were prepared via the sol-gel process. The powders and ceramics were characterized by XRD， SEM and TEM. The dielectric properties of the ceramics were also measured. The influences of calcination temperature and Mn concentration on the microstructure， dielectric properties and phase composition of BaTiO₃ nano-powders and ceramics were discussed. The results indicated that the BaTiO₃-based powders doped with 1.0mol% Mn were mainly in cubic BaTiO₃ phase， but the tetragonal phase became more evident when the calcination temperature increased. After sintering， Mn-doped ceramics were mainly composed of cubic BaTiO₃. Specially， a new phase of hexagonal crystal BaTiO₃ and BaMnO₃ existed in the ceramics doped with 5.0mol% Mn and the ceramic grains were in ‘clintheriform’. The structure of ‘clintheriform’ led to the poor densification of ceramics， reducing the dielectric constant obviously. The dielectric constants of BaTiO₃ ceramics first increased and then decreased as the Mn concentration increased. The room temperature dielectric constant was 2 290 and the lowest dielectric loss was 0.004 when the Mn concentration was 0.5mol%.     

Hydrothermal synthesis, structure and property of nano-BaTiO3-based dielectric materials

A series of Ba_1-xSr_xTi_1-yZr_yO₃ (0≤x≤0.5, 0≤y≤0.4) and BA_1?xZn_xTi_1?ySn_yO₃ (0≤x≤0.3, 0≤y≤0.3) solid solutions were synthesized by low-temperature/low-pressure hydrothermal method below 170°C, 0.8 MPa. XRD pattern and cell parameters-composition figures of these prepared powders demonstrated that they are completely miscible solid solutions based on BaTiO₃. Furthermore, TEM showed that they have a shape of uniform, substantially spherical particles with an average particle size of 70 nm in diameter. The sintered ceramics of those powders doped by Sr²⁺ and Zr⁴⁺ or Zn²⁺ and Sn⁴⁺ have dielectric constant twelve times higher than and dielectric loss 1/6 those of pure BaTiO₃ phase at room temperature.     

Nd-doped barium titanate ceramics with various Ti/Ba ratios prepared by sol-gel method

The Nd-doped BaTiO3 nanocrystalline powders and ceramics with different Ti/Ba ratios were prepared by sol-gel method. Phases and microstructures of the Nd-doped BaTiO3 based powders and ceramics were characterized by XRD, SEM and TEM methods. The results revealed that the powders synthesized by sol-gel method were nanometer scale (30-60 nm) and were mainly composed of cubic BaTiO3 with a small amount of BaCO3. After sintering at high temperature, both cubic BaTiO3 and BaCO3 were transformed into tetrahedron BaTiO3 phase. The dielectric properties of the ceramics were also determined and the influence of Ti/Ba ratio on the dielectric properties was discussed. The Tc did not change with the variation of Ti/Ba ratio, while theεmax increased firstly and then decreased. The excess TiO2 is benefit for the modification of ceramics' microstructure and dielectric properties.     

Synthesis, structure and dielectric properties of Ba1-xSrxMyTi1-yO3 (M = Zr, Sn)

A series of Ba_1-xSr_xM_yTi_1-yO₃ (M = Zr, Sn, 0?x?0.4, 0?y?0.3) solid solutions were synthesized with the soft chemical method below 100 °C. XRD pattern and cell parameters-composition figures of the prepared powder demonstrate that they are completely miscible solid solutions based on BaTiO₃. Furthermore, TEM shows that they have a shape of uniform, substantially spherical particles with an average particle size of 70 nm in diameter. The sintered ceramics of the powder doped with Sr²+and Zr⁴⁺ or Sn⁴⁺ have dielectric constant eight times higher and dielectric loss thirty per cent lower than those of pure BaTiO₃ phase at room temperature.