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1.
The electrical properties of layered perovskite-like compounds with the general formula Bi
m + 1Fe
m − 3Ti3O3m + 3 have been studied in relation to their physicochemical properties and structure. 相似文献
2.
The formation mechanisms of Li x Na1 ?x Ta y Nb1 ? y O3 perovskite solid solutions in the Li2CO3-Na2CO3-Nb2O5-Ta2O5 system have been studied by x-ray diffraction, differential thermal analysis, thermogravimetry, IR spectroscopy, and mass spectrometry at temperatures from 300 to 1100°C. The results indicate that the synthesis of Li x Na1 ? x Ta y Nb1 ? y O3 solid solutions involves a complex sequence of consecutive and parallel solid-state reactions. An optimized synthesis procedure for Li x Na1 ? x Ta y Nb1 ? y O3 solid solutions is proposed. 相似文献
3.
The physicochemical properties of BaO-Bi2O3-B2O3 glasses have been studied. The effect of KBF4 additions on the properties of the glasses has been examined. The transmission of the glasses has been correlated with their local structure and composition. 相似文献
4.
O. G. Reznitskikh N. I. Lobachevskaya V. G. Zubkov N. D. Koryakin V. D. Zhuravlev V. G. Bamburov 《Inorganic Materials》2007,43(1):73-77
The phase equilibria in the ternary system La2O3-Nb2O5-Nb have been studied at subsolidus temperatures in vacuum (6.65 × 10?3 Pa), and the temperature stability limits of LaNb7O12 have been determined in vacuum and during heating in air. 相似文献
5.
Josef Jirák Ladislav Koudelka Jaroslav Pospíšil Petr Mošner Lionel Montagne Laurent Delevoye 《Journal of Materials Science》2007,42(20):8592-8598
Glasses of the ternary system ZnO–Bi2O3–P2O5 were prepared and studied in two compositional series 50ZnO–xBi2O3–(50 − x)P2O5 and (50 − y)ZnO–yBi2O3–50P2O5. Two distinct glass-forming regions were found in the 50ZnO–xBi2O3–(50 − x)P2O5 glass series with x = 0–10 and 20–35 mol.% Bi2O3. All prepared Bi2O3-containing glasses reveal a high chemical durability. Small additions of Bi2O3 (∼5 mol.%) improve thermal stability of glasses. All glasses crystallize on heating within the temperature range of 505–583 °C.
Structural studies by Raman and 31P MAS NMR spectroscopies showed the rapid depolymerisation of phosphate chains within the first region with x = 0–15 and the presence of isolated Q0 phosphate units within the second region with x = 20–35. Raman studies showed that bismuth is incorporated in the glass structure in BiO6 units and their vibrational bands were observed within the spectral region of 350–700 cm−1. The evolution of properties and the spectroscopic data are both in accordance with a network former effect of Bi2O3. 相似文献
6.
L. D. Ivanova L. I. Petrova Yu. V. Granatkina V. S. Zemskov O. B. Sokolov S. Ya. Skipidarov N. I. Duvankov 《Inorganic Materials》2009,45(2):123-128
Extruded n-type materials based on Bi2Te3-Bi2Se3 alloys containing 6 to 40 mol % Bi2Se3 have been investigated using microstructural analysis and thermoelectric measurements at room temperature and in the range 100–400 K. Their electrical properties have been compared to those of single-crystal analogs. Compositions have been found at which the extruded materials offer the highest thermoelectric performance in different temperature ranges. 相似文献
7.
N. A. Gorodylova V. N. Baumer I. V. Zatovsky A. A. Babarik N. S. Slobodyanik O. V. Shishkin 《Inorganic Materials》2011,47(2):156-162
We have studied general trends of crystallization from high-temperature solutions in the K2O-P2O5-V2O5-Bi2O3 system at P/V = 0.5?2.0, K/(P + V) = 0.7?1.4, and Bi2O3 contents from 25 to 50 wt % and identified the stability regions of BiPO4, K3Bi5(PO4)6, K2Bi3O(PO4)3, and K3Bi2(PO4)3 ? x (VO4) x (x = 0?3) solid solutions. The synthesized compounds have been characterized by X-ray powder diffraction and IR spectroscopy, and the structure of two solid solutions has been determined by single-crystal X-ray diffraction (sp. gr. C 2/c): K3Bi2(PO4)2(VO4), a = 13.8857(8), b = 13.5432(5), c = 6.8679(4) Å, β = 114.031(7)°; K3Bi2(PO4)1.25(VO4)1.75, a = 13.907(4), b = 13.615(2), c = 6.956(2) Å, β = 113.52(4)°. 相似文献
8.
Bismuth(III) and germanium(IV) oxides are used as precursors for the crystal growth of bismuth orthogermanate. The chlorine content of the starting oxides is critical to the engineering performance of this material. We propose a simple, high-speed technique for determining the chlorine content of bismuth(III) and germanium(IV) oxides, down to 5 × 10?4 wt %, using capillary electrophoresis. 相似文献
9.
Tianye Wang Wanyi Liu Yunhang Gao Shuxia Liu 《Journal of Materials Science: Materials in Electronics》2017,28(20):14949-14953
In this study, the effects of sodium oleate on synthesis of Bi2WO6/Bi2O3 loaded reduced graphene oxide photocatalyst was studied. The as-prepared composites were characterized by X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, UV–visible diffuse reflectance and photoluminescence spectroscopy. The results suggested that addition of sodium oleate not only promoted synthesis of Bi2O3, but also enhanced the reduction of GO to graphene. When the amount of sodium oleate was 4 mol (Bi:SO?=?1:1), Bi2WO6/Bi2O3@RGO to the best visible-light photocatalytic activity can be synthesized by a facile one-step solvothermal process without further reduction reaction. Hence, it indicated that sodium oleate could affect the synthesis of the as-prepared composites and the photocatalytic activity for degradation of RhB. This study did provide not only a facile method to synthesize Bi2WO6/Bi2O3@RGO, but also a method to reduce graphene oxide to graphene. 相似文献
10.
The phase formation and reaction kinetics in the TiO2-Cr2O3 system have been studied by x-ray diffraction and electron microscopy. The Cr2O3 solubility in TiO2 has been accurately determined, and the rate parameters of the formation of solid solutions in this system have been evaluated. The results demonstrate that Cr2O3 dissolves in rutile and not in anatase. Cr2O3 markedly reduces the temperature of the anatase-rutile phase transition. 相似文献
11.
The limits of the LiLaO2-and Li2ZrO3-based solid solutions in the LiLaO2-Li2ZrO3 system have been determined: 0–10 mol % Li2ZrO3 and 0–5 mol % LiLaO2, respectively. We have studied the transport properties (electronic conductivity, temperature and composition dependences of conductivity and activation energy) of lithium lanthanate and the solid solutions in the LiLaO2-Li2ZrO3 system. Conduction in LiLaO2 is likely due to lithium ion transport through a polyhedral network. 相似文献
12.
A. A. Zatsiupa L. A. Bashkirov I. A. Vialikanava G. S. Petrov S. V. Shevchenko 《Inorganic Materials》2016,52(4):361-366
Bi2–хLaхFe4O9 and Bi2Fe4–2xTixCoxO9 ferrites have been prepared by solid-state reactions at a temperature of 1073 K. X-ray diffraction data indicate that, in the Bi2–хLaхFe4O9 system, the limiting degree of La3+ substitution for Bi3+ ions in Bi2Fe4O9 does not exceed 0.05 and that the limiting degree of substitution in the Bi2Fe4–2xTixCoxO9 system lies in the range 0.05 < x < 0.1. The specific magnetization and specific magnetic susceptibility of the samples have been measured at temperatures from 5 to 300 K in a magnetic field of 0.86 T. The field dependences of magnetization obtained for the Bi2–хLaхFe4O9 and Bi2Fe4–2xTixCoxO9 ferrites at temperatures of 300 and 5 K demonstrate that partial isovalent substitution of La3+ for Bi3+ ions in Bi2Fe4O9 and heterovalent substitution of Ti4+ and Co2+ ions for two Fe3+ ions leads to partial breakdown of the antiferromagnetic state and nucleation of a ferromagnetic state. 相似文献
13.
Contact interaction between Bi2O3-SiO2 melts and gold has been studied by the sessile drop method. The melts are shown to spread over gold and dissolve it. 相似文献
14.
The combustion synthesis, microstructure, chemical composition, and phase composition of cast Al2O3-Cr2O3 materials are described. The synthesized solid solutions are based on corundum or chromia, depending on the Al2O3 and Cr2O3 contents. Using self-propagating high-temperature synthesis, a cast aluminum oxynitride is obtained for the first time. 相似文献
15.
V. M. Chumarev V. P. Mar’evich A. V. Larionov A. Ya. Dubrovskii 《Inorganic Materials》2011,47(3):267-272
Reactions of vanadium, niobium, and tantalum pentoxides with aluminum nitride have been studied using X-ray diffraction. At
temperatures from 1000 to 1600°C, we have identified various V, Nb, and Ta nitrides. The composition of the niobium and tantalum
nitrides depends on the reaction temperature. The tendency toward nitride formation becomes stronger in the order V2O5 < Ta2O5 < Nb2O5. 相似文献
16.
The thermoelectric power and d.c electrical conductivity of x V2O5⋅40CaO⋅(60−x)P2O5 (10 ≤ x ≤ 30) glasses were measured. The Seebeck coefficient (Q) varied from +88 μ V K−1 to −93 μV K−1 as a function of V2O5 mol%. Glasses with 10 and 15 mol% V2O5 exhibited p-type conduction and glasses with 25 and 30 mol% V2O5 exhibited n-type conduction. The majority charge carrier reversal occurred at x = 20 mol% V2O5. The variation of Q was interpreted in terms of the variation in vanadium ion ratio (V5 +/V4 +). d.c electrical conduction in x V2O5⋅40CaO⋅(60−x)P2O5 (10 ≤ x ≤ 30) glasses was studied in the temperature range of 150 to 480 K. All the glass compositions exhibited a cross over from
small polaron hopping (SPH) to variable range hopping (VRH) conduction mechanism. Mott parameter analysis of the low temperature
data gave values for the density of states at Fermi level N (EF) between 1.7 × 1026 and 3.9 × 1026 m−3 eV−1 at 230 K and hopping distance for VRH (RVRH) between 3.8 × 10−9m to 3.4 × 10−9 m. The disorder energy was found to vary between 0.02 and 0.03 eV. N (EF) and RVRH exhibit an interesting composition dependence. 相似文献
17.
We have measured the thermal conductivity of Bi2Te3-Sb2Te3-Gd2Te3 solid solutions at temperatures from ~80 to 300 K and have determined the electronic and lattice components of their total thermal conductivity and the contributions of Sb2Te3 and Gd2Te3 to their thermal resistance. The results indicate that heat in these materials is transported largely by phonons and that three-phonon processes play a key role in determining the lattice thermal conductivity of the solid solutions. 相似文献
18.
The study of electrical conductivity of 30Li2O: (70 − x) B2O3: xV2O5 glass samples has been carried out. The results have been explained by dividing the temperature range into two regions. In
region I, conductivity shows Arrhenius behaviour for all the samples. The conductivity increases with addition of V2O5. The results have been explained in the light of Anderson and Stuart Model. In region II, an anomalous enhancement in the
conductivity is observed for all the samples up to certain temperature beyond which the conductivity decreases. The enhancement
in the conductivity in the annealed glass sample has been attributed to nanocrystallization. 相似文献
19.
Single-crystal and polycrystalline samples of Sc4Ti3O12 have been shown to contain nanodomains (10–50 nm) with different degrees of ordering, coherent with the fluorite-like matrix. The oxygen-ion conductivity of this compound has been determined in the range 300–1000°C in air using impedance spectroscopy. The nanostructured single-crystal and polycrystalline samples are close in the activation energy for bulk conduction at both low and high temperatures: ?1.26 and 1.29 eV in the range 300–775°C, ?1.98 and 2.07 eV in the range 775–1000°C. 相似文献
20.
Liang Fang Zhao Yang Hui Zhang Chunchun Li Xiyang Peng Changzheng Hu Dongjin Chu 《Journal of Materials Science: Materials in Electronics》2011,22(9):1208-1212
Polycrystalline samples of Ba4Ln2Fe2Ta8O30 (Ln = La and Nd) were prepared by a high temperature solid-state reaction technique. The formation, structure, dielectric
and ferroelectric properties of the compounds were studied. Both compounds are found to be paraelectrics with filled tetragonal
tungsten bronze (TB) structure at room temperature. Dielectric measurements revealed that the present ceramics have exceptional
temperature stability, a relatively small temperature coefficient of dielectric constant (τ
ε
) of −25 and −58 ppm/°C, with a high dielectric constant of 118 and 96 together with a low dielectric loss of 1.2 × 10−3 and 2.8 × 10−3 (at 1 MHz) for Ba4La2Fe2Ta8O30 and Ba4Nd2Fe2Ta8O30, respectively. The measured dielectric properties indicate that both materials are possible candidates for the fabrication
of discrete multilayer capacitors in microelectronic technology. 相似文献