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91.
《矿物冶金与材料学报》2002,(1):48-52
A novel process termed low-temperature combustion-synthesis (LCS) of Ba(NO3)-TiO-C6H8O7H2O system was investigated at the initial temperature of 600℃ and ultrafine BaTiO3 powders with a particle size of 200€?350nm were prepared. It was found that the molar ratio of NO/citric acid and the homogeneity of combustion have remarkable effect on the characteristics of the powder. The reaction mechanism of LCS BaTiO3 powders was proposed on the basis of thermodynamic analysis. 相似文献
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93.
复合掺杂对BaTiO3瓷介电常数温度特性的影响 总被引:2,自引:0,他引:2
研究了Dy-Nb、Ce-Nb氧化物复合掺杂对BaTiO3瓷温度特性的影响。结果表明,能使BaTiO3瓷的介电常数-温度关系曲线变得相当平缓。对造成此结果的原因,进行了理论分析和讨论。 相似文献
94.
Jamil Hantash Alan Bartlett Georges Dénès Abdualhafeed Muntasar Philip Oldfield 《Hyperfine Interactions》2005,166(1-4):373-378
A new method of preparation of high performance fluoride ion conductor, BaSnF4, by water leaching of newly discovered barium tin(II) chloride fluorides, has been designed, and the materials have been studied and compared to the solid prepared by the usual dry method. The unit-cell parameters and crystallite dimensions were found to vary with the method of preparation. In addition, the crystallite dimensions were found to be highly anisotropic for the samples obtained by the wet method. The Mössbauer spectrum is made of a large tin(II) quadrupole doublet, and a broad tin(IV) oxide peak due to surface oxidation. The tin(II) spectrum is in agreement with covalently bonded tin(II) having a strongly stereoactive lone pair. An unusually high dependence of the quadrupole splitting at low temperatures was observed (5.8 times larger than for α-SnF2). 相似文献
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97.
用氯化钡法分析混合碱,当试样中混合碱含量为2g时(指500 ml待测液中碳酸钠和碳酸氢钠混合物的含量)结果准确,但当试样中混合碱含量大于2 g时,测定误差较大,可大于40%(相对误差)。这是由于BaCO_3吸附OH~-离子的结果,介绍了应用系数校正法,消除了这一误差,方法简便、准确、快速,相对误差可达0.2%以下。并对BaCO_3的吸附机理进行了初步的探讨。 相似文献
98.
《华东理工大学学报(自然科学版)》2012,40(1)
通过固相反应法制备Mn、Zr共掺杂钛酸锶钡/氧化镁陶瓷粉体,经干压成型后在空气气氛中于l450℃烧结4h,通过扫描电子显微镜和X射线衍射研究了ZrO2和MnO2共掺杂的Bao6Sro4TiO3/MgO复合陶瓷材料的微结构和介电性能。结果表明:Zr02可以显著降低材料的介电常数和介电损耗,有效提高了陶瓷材料的温度稳定性;随ZrO2添加量的增加,体系的晶胞参数略有增加,MgO在钛酸锶钡中以独立相的形式存在:制备出的BST铁电陶瓷材料的25℃相对介电常数较低(&〈110),介质损耗小于1.0×10^-3(在频率为10kHz时),温度系数小于6.012×10^-3,可调性大于20%(8.0kV/mm),适用于制作移相器。 相似文献
99.
(Pb0.5Ba0.5)ZrO3 (PBZ) and 1 mol% Mn-doped (Pb0.5Ba0.5)ZrO3 (Mn-PBZ) sol were successfully fabricated, and corresponding thin films were deposited on Pt(1 1 1)/TiO2/SiO2/Si(1 0 0) substrates by spin-coating method. Effects of Mn doping on the microstructure and electrical properties of PBZ thin films were investigated systemically. X-ray diffraction patterns showed that both films had a polycrystalline perovskite structure, and that the degree of (1 1 1) orientation were increased by Mn doping. Dielectric measurements illustrated that Mn-doped PBZ thin films not only had a larger dielectric constant, but also possessed a smaller dielectric loss. Accordingly, the tunability and the figure of merit of PBZ films were improved by Mn doping. 相似文献
100.
Several barium plumbate (BaPbO3) solid samples, made from PbO and BaCO3 powder by chemistry liquid-phase coprecipitation, were investigated before and after γ-irradiation. The solid samples were irradiated by a 60Co γ-irradiation source whose dose rate is about 0.7?kGy per hour. The irradiation times were 0, 72, 144, 216, 288 and 360?h. Then, the four-probe method, X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) were used to indicate the changes in electrical conductivity and microstructure of BaPbO3 after γ-irradiation. The XRD results indicated that the content of PbO was reduced as the irradiation dose was increased and eventually vanished from the surface of samples. However, there was no new obvious substance phase found from the XRD atlas. It seems that the PbO transformed into nearly amorphous Pb5O8. The conjecture could be proved by the results of annealing experiment and SEM. The XPS results seem to show that the microstructure of BaPbO3 was slightly changed. 相似文献