共查询到20条相似文献,搜索用时 24 毫秒
1.
A. A. Solov’ev N. S. Sochugov A. V. Shipilova K. B. Efimova A. E. Tumashevskaya 《Russian Journal of Electrochemistry》2011,47(4):494-502
Data on the mid-temperature solid-oxide fuel cells (SOFC) with thin-film ZrO2-Y2O3 (YSZ) electrolyte are shown. Such a fuel cell comprises a carrying Ni-YSZ anode, a YSZ electrolyte 3–5 μm thick formed by
vacuum ion-plasma methods, and a LaSrMnO3 cathode. It is shown that the use of a combined method of YSZ electrolyte deposition, which involves the magnetron deposition
of a 0.5–1.5-μm thick sublayer and its pulse electron-beam processing allows a dense nanostructured electrolyte film to be
formed and the SOFC working temperature to be lowered down as the result of a decrease in both the solid electrolyte Ohmic
resistance and the Faradaic resistance to charge transfer. SOFC are studied by the methods of voltammentry and impedance spectroscopy.
The maximum power density of the SOFC under study is 250 and 600 mW/cm−2 at temperatures of 650 and 800°C, respectively. 相似文献
2.
Chen-Chia Chou Shen-Da Tsai Wen-Hsiang Tu Yu-En Yeh-Liu Hsien-Lung Tsai 《Journal of Sol-Gel Science and Technology》2007,42(3):315-322
Fabrication of ferroelectric Pb(Zr0.52Ti0.48)O3 (PZT) thick films on a Pt/Ti/SiO2/Si substrate using powder-mixing sol-gel spin coating and continuous wave CO2 laser annealing technique to treat the specimens with at a relatively low temperature was investigated in the present work.
PZT fine powders were prepared by drying and pyrolysis of sol-gel solutions and calcined at temperatures from 400 to 750°C.
After fine powder-containing sol-gel solutions were spin-coated on a substrate and pyrolyzed, CO2 laser annealing was carried out to heat treat the specimens. The results show that laser annealing provides an extremely
efficient way to crystallize the materials, but an amorphous phase may also form in the case of overheating. Thicker films
absorb laser energy more effectively and therefore melt at shorter periods, implying a significant volume effect. A film with
thickness of 1 μm shows cracks and rough surface morphology and it was difficult to obtain acceptable electrical properties,
indicating importance of controlling interfacial stress and choosing appropriate size of the mixing powders. On the other
hand, a thick film of 5 μm annealed at 100 W/cm2 for 15 s exhibits excellent properties (P
r = 36.1 μC/cm2, E
c = 19.66 kV/cm). Films of 10 μm form a melting zone at the surface and a non-crystallized bottom layer easily at an energy
density of 100 W/cm2, showing poor electrical properties. Besides, porosity and electrical properties of thick films can be controlled using appropriate
processing parameters, suggesting that CO2 laser annealing of modified sol-gel films is suitable for fabricating films of low dielectric constants and high crystallinity. 相似文献
3.
Lili Chen Mingrong Shen Liang Fang Yu Xu 《Journal of Sol-Gel Science and Technology》2007,42(3):299-303
A TiO2 thin buffer layer was introduced between the (Pb0.4Sr0.6)TiO3 (PST) film and the Pt/Ti/SiO2/Si substrate in an attempt to improve their electrical properties. Both TiO2 and PST layers were prepared by a chemical solution deposition method. It was found that the TiO2 buffer layer increased the (100)/(001) preferred orientation of PST and decreased the surface roughness of the films, leading
to an enhancement in electrical properties including an increase in dielectric constant and in its tunability by DC voltage,
as well as a decrease in dielectric loss and leakage current density. At an optimized thickness of the TiO2 buffer layer deposited using 0.02 mol/l TiO2 sol, the 330-nm-thick PST films had a dielectric constant, loss and tunability of 1126, 0.044 and 60.7% at 10 kHz, respectively,
while the leakage current density was 1.95 × 10−6 A/cm2 at 100 kV/cm. 相似文献
4.
T. Zhang L. Kong Z. Zeng H. Huang P. Hing Z. Xia J. Kilner 《Journal of Solid State Electrochemistry》2003,7(6):348-354
A 20% GdO1.5 doped ceria solid solution with a small amount of MnO2 doping (≤5% molar ratio) was prepared via the mixed oxide method from high-purity commercial powders with grain size around
0.2–0.5 μm. X-ray diffraction analysis indicated that all the samples exhibited the fluorite structure, and no new phase was
found. The data from dilatometeric measurements and scanning electron microscopy observations revealed that 1% Mn doping reduced
the sintering temperature by over 150 °C, and enhanced the densification and grain growth. Mn doping has little effect on
grain interior conductivity, but a marked deterioration in grain boundary behavior is observed. This leads to a lower total
conductivity in comparison with the undoped Ce0.8Gd0.2O2–δ. Therefore, for solid oxide fuel cells (SOFCs) with Mn-containing compounds as electrodes, optimization of electrode fabrication
conditions is needed to prevent the formation of a lower conductivity layer at the electrode/electrolyte interface since Mn
will diffuse from the electrode side to the electrolyte during fabrication and operation of SOFCs.
Electronic Publication 相似文献
5.
Yong Hong Wang Yang Zhang Xing Qin Liu Guang Yao Meng 《Journal of Sol-Gel Science and Technology》2007,41(3):267-275
A simple approach namely sol-coated technique has been developed for the low cost fabrication of macroporous ceramic under
a far below common sintering temperature of alumina with large dimension grains. The prepared green support shows higher sinteractive
than the one treated by wet impregnation method under the same sintering conditions. The support possesses great potential
applications with 6.63–7.71 μm in pore size, 39% open porosity as well as >45 MPa mechanical strength at the sintering temperature
range of 1350°– 1500°C. The results indicate that the nitrogen gas flux and pure water permeation value was 51 252.35 m3 m−2 h−1 bar−1, 98.43 m3 m−2 h−1 bar−1, respectively, which were more dependent on the pore structure and pore size distribution than open porosity. 相似文献
6.
Francesco Bozza Riccardo Polini Enrico Traversa 《Electrochemistry communications》2009,11(8):1680-1683
Remarkable power density was obtained for anode-supported solid oxide fuel cells (SOFCs) based on La0.8Sr0.2Ga0.8Mg0.2O3−δ (LSGM) electrolyte films, fabricated following an original procedure that allowed avoiding undesired reactions between LSGM and electrode materials, especially Ni. Electrophoretic deposition (EPD) was used for the fabrication of 30 μm-thick electrolyte films. Anode supports were made of La0.4Ce0.6O2−x (LDC). The LSGM powder was deposited by EPD on an LDC green tape-cast membrane added with carbon powder, both as pore former and substrate conductivity booster. A subsequent co-firing step at 1490 °C produced dense electrolyte films on porous LDC skeletons. Then, a La0.8Sr0.2Fe0.8Co0.2O3−δ (LSFC) cathode was applied by slurry-coating and calcined at 1100 °C. Finally, the porous LDC layer was impregnated with molten Ni nitrate to obtain, after calcination at 900 °C, a composite NiO–LDC anode. Maximum power densities of 780, 450, 275, 175, and 100 mW/cm2 at 700, 650, 600, 550, and 500 °C, respectively, were obtained using H2 as fuel and air as oxidant, demonstrating the success of the processing strategy. As a comparison, electrolyte-supported SOFCs made of the same materials were tested, showing a maximum power density of 150 mW/cm2 at 700 °C, more than 5 times smaller than the anode-supported counterpart. 相似文献
7.
The metal-ferroelectric-semiconductor (MFS) heterostructure has been fabricated using Bi3.25La0.75Ti3O12 (BLT) as a ferroelectric layer by sol-gel processing. The effect of annealing temperature on phase formation and electrical
characteristics of Ag/BLT/p-Si heterostructure were investigated. The BLT thin films annealed at from 500°C to 650°C are polycrystalline,
with no pyrochlore or other second phases. The C-V curves of Ag/BLT/p-Si heterostructure annealed at 600°C show a clockwise C-V ferroelectric hysteresis loops and obtain good electrical properties with low current density of below 2×10−8 A/cm2 within ±4 V, a memory window of over 0.7 V for a thickness of 400 nm BLT films. The memory window enlarges and the current
density reduces with the increase of annealing temperature, but a annealing temperature over 600°C is disadvantageous for
good electrical properties. 相似文献
8.
Jaekyung Yoon Sanghyun Bae Jinwook Ha Hyunku Joo 《Research on Chemical Intermediates》2009,35(3):287-297
In this study, an anodized tubular TiO2 electrode (ATTE) on titanium foil was prepared and used both as a photoanode and a cathode in an enzymatic photoelectrochemical
system to split water into oxygen and hydrogen. The effect of applied voltage when anodized, thickness of the foil, electrolytes,
annealing temperature, and cathodes was investigated (optimum conditions: 20 V of applied voltage in 0.5 vol.% of hydrofluoric
acid, 0.25-mm foil thickness, and 450–650°C annealing temperature). The samples with higher activities had similar X-ray diffraction
(XRD) patterns, clearly indicating that the samples showing the highest evolution rate were composed of both anatase and rutile,
while those showing a lower evolution rate were made of either anatase or rutile. The ATTE successfully replaced the Pt mesh
cathode and the immobilization of the enzyme enhanced the H2 evolution by 50% (from ca. 66 to 99 μmol/(h × cm2)). Moreover, the use of KOH instead of Tris–HCl buffer in a cathodic compartment further increased the H2 evolution to 115 μmol/(h × cm2). 相似文献
9.
V. H. Martínez-Landeros Bruce E. Gnade M. A. Quevedo-López R. Ramírez-Bon 《Journal of Sol-Gel Science and Technology》2011,59(2):345-351
In this work we report the performance of permeation barriers based on organic/inorganic multilayer stacks. We have used PMMA-SiO2 (poly methyl methacrylate-silica) hybrid films synthesized through a sol–gel route as organic–inorganic components, whereas
Al2O3 thin films were used as the inorganic component. The hybrid layers were deposited by dip coating and the Al2O3 by atomic layer deposition (ALD), films were prepared on polyethylene naphthalene (PEN) substrates. The permeability of the
films and stacks is evaluated using helium as the diffusion gas in a custom made ultra-high vacuum system. The results show
that permeability for PEN is reduced from 5 × 10−3 g/m2-day to about 9 × 10−5 g/m2-day for the best multiple barrier evaluated. Increased barrier properties are due to the increasing in the path and hence
the lag-time of the permeating gas. In particular, we report the surface roughness of the different layers and its impact
on the barrier performance. The hybrid layers reduced notably the roughness of the bare PEN substrate improving the quality
of the Al2O3 layer in the barrier. The optical transmittance of the barriers in the visible region is higher than 80% in all the studied
cases. 相似文献
10.
Magnetic Co3O4 nanoparticles were prepared by using microporous regenerated cellulose films as sacrificial scaffolds. The cellulose macromolecules
and the porous structure of the films made them used as spatially confined reacting sites where Co(OH)2 nanoparticles could be synthesized in situ. When the cellulose matrix was removed by sintering at 500 °C, Co3O4 nanoparticles were obtained. XRD and XPS indicated that the prepared nanoparticles were pure Co3O4 without any impurity. TEM and SEM images revealed that the particle size of the nanoparticles was smaller than 100 nm. The
nanoparticles had weak ferromagnetic properties at 25 °C. Furthermore, the pronounced quantum confinement effects of the synthesized
nanoparticles have been observed, the optical bandgap energies determined were about 1.92 ~ 2.12 and 2.74 ~ 2.76 eV for O2− → Co3+ and O2− → Co2+ charge-transfer processes, respectively. Furthermore, the resulted Co3O4 nanoparticles behaved stable electrochemical performance with promising applications in the electrode for lithium ion battery. 相似文献
11.
Jun Wang Tianjin Zhang Hongying Xia Junhuai Xiang Wenkui Li Shuwang Duo 《Journal of Sol-Gel Science and Technology》2008,47(1):102-106
Compositionally graded Ba1−x
Sr
x
TiO3 (BST) (0 ≤ x ≤ 0.4) thin films were fabricated on Pt/Ti/SiO2/Si and YSZ/Pt/Ti/SiO2/Si substrates by a modified sol–gel technique. The YSZ buffer layer was prepared by RF magnetron sputtering. The microstructure
of the graded BST films was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force
microscopy (AFM). The results showed that all the films have uniform and crack-free surface with a perovskite structure. The
graded BST film with an YSZ buffer layer has larger dielectric constant and lower dielectric loss. The leakage current density
of the graded BST film with an YSZ buffer layer lowers two orders than the film without buffer layer. The improved electric
properties of the graded films with an YSZ buffer layer was attributed to the YSZ buffer layer act as an excellent seeding
layer to enhance the graded BST film growth. 相似文献
12.
L. A. Dunyushkina A. I. Vshivkova A. A. Pankratov B. D. Antonov V. P. Gorelov 《Russian Journal of Electrochemistry》2010,46(7):767-773
The surface of ceramic electrolyte ZrO2 + 9 mol % Y2O3, hereinafter referred to as YSZ (abbreviated yttria stabilized zirconia), was modified with 0.1 to 0.2 μm oxide films of
ZrO2, Y2O3, and YSZ (same composition as substrate) by dip coating in alcohol solutions of the relevant salts and further annealing.
The results of scanning electronic microscopy and X-ray diffraction evidence epitaxial film growth. By means of impedance
spectroscopy at the temperatures of 500 to 600°C, the effect of YZS electrolyte surface modification with ZrO2, Y2O3, and YSZ films to the polarization resistance of silver electrode was studied. 相似文献
13.
A. A. Kurteeva N. M. Bogdanovich D. I. Bronin N. M. Porotnikova G. K. Vdovin A. A. Pankratov S. M. Beresnev L. A. Kuz’mina 《Russian Journal of Electrochemistry》2010,46(7):811-819
The electrodes of solid-oxide fuel cells (SOFCs) must be characterized by high conductivity to decrease ohmic losses and sufficient
porosity to provide high gas diffusion rate. In the cases, when the SOFC electrodes are substrates, they must be synthesized
at the temperature above the temperature of formation of their solid-electrolyte coating. Herewith, manufacturing of supporting
electrodes with the required micro-structure is rather complicated. The present paper studies the effect of the method of
manufacturing of the initial La0.6Sr0.4MnO3 (LSM) powders, their degree of dispersion, introduction of sintering additives and pore agents on their microstructure, conductivity,
and possibility of adjusting the temperature of SOFC cathodic substrate formation at which the required characteristics are
reached. It is shown that sintering of cathodic substrates to the relative density of 65–70% can be carried out at the temperatures
from 1050 to 1350–1400°C, which would allow obtaining electrolyte films of powders with different sintering ability on such
substrates. The average pore size in cathodic substrates can be varied in the range of 0.4 to 2.5 μm by using the initial
LSM powder with different dispersion degree and by employing graphite as a pore agent. At 900°C, conductivity of cathodic
substrates of LSM grows at an increase in their relative density from 50% to 70% approximately from 50 to 100 S/cm and weakly
depends on the dispersion degree of the initial powders. 相似文献
14.
Žaneta Dohnalová Petra Šulcová Miroslav Trojan 《Journal of Thermal Analysis and Calorimetry》2010,101(3):973-978
The main aim of this work was to synthesize the magnesium orthostannate doped by terbium cations and tested whether these
materials can be used for colouring of the different materials, e.g. organic binder and ceramic glazes. Initial composition
of pigments was counted according the general formula 2MgO(1 − x)SnO2–xTbO2, where values of x varied from 0.1 to 0.5 in 0.1 steps. The simultaneous TG/DTA measurements of mixture containing tin oxide, magnesium carbonate
hydroxide and terbium oxide showed that the formation of a new compound started at temperature 1,029 °C, but single-phase
system was not prepared. Granulometric compositions of samples that were prepared by calcining at temperatures 1,300–1,400 °C
are characterized by values of median (d
50) in range 4–8 μm. The calcining temperature 1,500 °C caused the increase of the particle sizes at around 12 μm. The composition
of sample 2MgO–1.5SnO2–0.5TbO2 and heating temperature 1,500 °C are the most suitable conditions for preparation of colourfully interesting pigment that
can be recommended also for colouring of ceramic glazes. Especially, for colouring of decorative lead containing glaze G 07091
containing 5 wt% of PbO and 8 wt% of Al2O3. 相似文献
15.
S. A. Kandil H. A. Hanafi H. Aglan Z. A. Saleh 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(3):609-614
The adsorption behaviour of La/Ce system on Dowex 50W-X8 in different media, namely, nitric acid, acetate buffer and citrate
buffer was studied as a function of the concentration of nitric acid and buffer pH. In addition, in cation-exchange column
chromatography experiments, three different eluants, namely, citrate buffer of pH 5.5, 0.1 M EDTA and 0.2 M α-HIBA, were employed
for separation of Ce(III) from La(III). The optimum conditions for improvement of radiochemical separation of no-carrier-added
139Ce from proton irradiated lanthanum were applied using the most suitable chelating agent 0.2 M α-HIBA. The purification of
139Ce from macro amount of La(III) was done using two columns in a sequence. The target was prepared by pressing. The production
of high radionuclidic and chemical purity 139Ce via irradiation of lanthanum oxide target at MGC-20 cyclotron of proton energy 14.5 MeV was described. The experimental
yield was found to be 200 kBq/μA h. 相似文献
16.
Reverse micellar microemulsions were utilised to synthesise stable lead titanate colloids from typical sol–gel type molecular
precursors. The particles of a few nanometres in diameter that formed by hydrolysis in the micelle cores demonstrated a nanocrystalline
texture without the need for thermal treatment. In a chemical solution deposition routine based on the nanoparticle dispersions,
ferroelectric PbTiO3 thin films showing excellent remanent polarisation of more than 50 μC cm−2 were derived. The electrical characteristics of the layers were correlated to their microstructure which was controlled by
the precursor composition and the annealing conditions. A columnar morphology that was realised by spinning on coatings of
up to 100 nm in individual thickness proved most favourable with respect to the ferroelectric performance of the films. 相似文献
17.
Ca3Co4O9 powder was prepared by a polyacrylamide gel route in this paper. The effect of the processing on microstructure and thermoelectric
properties of Ca3Co4O9 ceramics via spark plasma sintering were investigated. Electrical measurement shows that the Seebeck coefficient and conductivity
are 170 μV/K and 128 S/cm, respectively, at 700 °C, yielding a power factor value of 3.70 × 10−4 W m−1 K−2 at 700 °C, which is larger than that of Ca3Co4O9 ceramics via solid-state reaction processing. The polyacrylamide gel processing is a fast, cheap, reproducible and easily
scaled up chemical route to improve the thermoelectric properties of Ca3Co4O9 ceramics by preparing the homogeneous and pure Ca3Co4O9 phase. 相似文献
18.
P. M. Chavhan R. K. Sharma N. K. Kaushik 《Journal of Sol-Gel Science and Technology》2010,53(3):505-508
The 12BaO·7Al2O3 (B12A7) thin films have been prepared via sol–gel process. Optical and electrical properties of B12A7 films have been investigated.
The films were coated on soda lime float glass by the dip coating process, and annealed in air and hydrogen (H2) at 450 °C for 2 h. The UV absorption edge was red shifted for films annealed in H2 atmosphere. The B12A7 films had high transparency about 90% in wide visible range with maximum of 95% at 575 nm wavelength.
The sheet resistance of the 300 nm films corresponding to 90.57 and 0.974 kΩ per square has been observed for air and H2 annealed, respectively. 相似文献
19.
L. S. Cavalcante J. C. Sczancoski F. S. De Vicente M. T. Frabbro M. Siu Li J. A. Varela E. Longo 《Journal of Sol-Gel Science and Technology》2009,49(1):35-46
Ba[Zr0.25Ti0.75]O3 (BZT) thin films were synthesized by the complex polymerization method and heat treated at 400 °C for different times and
at 700 °C for 2 h. These thin films were analyzed by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy,
field emission gun-scanning electron microscopy (FEG-SEM) and atomic force microscopy (AFM), Ultraviolet–visible (UV–vis)
absorption spectroscopy, electrical and photoluminescence (PL) measurements. FEG-SEM and AFM micrographs showed that the microstructure
and thickness of BZT thin films can be influenced by the processing times. Dielectric constant and dielectric loss of BZT
thin films heat treated at 700 °C were approximately 148 and 0.08 at 1 MHz, respectively. UV–vis absorption spectra suggested
the presence of intermediary energy levels (shallow and deep holes) within the band gap of BZT thin films. PL behavior was
explained through the optical band gap values associated to the visible light emission components. 相似文献
20.
M. Mirzaii S. Seyyedi M. Sadeghi Z. Gholamzadeh 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(2):333-339
natCd electrodeposition on a copper substrate was investigated for production of 111In radionuclide. The electrodeposition experiments were carried out by alkaline plating baths. Operating parameters such as
pH, temperature, and current density are also optimized. The current efficiency was measured at different current densities.
The optimum conditions of the cadmium electrodeposition were as follows: 2.35 g L−1 cadmium, pH = 13, DC current density of ca 4.27 mA cm−2 at 25 °C temperature with 62.48 μm thickness. SEM photomicrographs demonstrated fine-grained structure of the deposit obtained
from the optimum bath. 相似文献