Deposition of inorganic bronze coatings over ceramic foams

2005 ◽  
Vol 20 (5) ◽  
pp. 1207-1215 ◽  
Author(s):  
M. Mann ◽  
G.E. Shter ◽  
G.S. Grader
Keyword(s):  
Intermediate Layer ◽  
Hydrogen Reduction ◽  
Tungsten Bronze ◽  
Impregnation Method ◽  
Ceramic Surface ◽  
Pure Alumina ◽  
Ceramic Foams ◽  
External Agent ◽  
Nacl Concentration ◽  
General Basis

A method for applying conductive inorganic tungsten bronze (NaxWO3) coatings over ceramic foams is presented. The general basis of bronze coating involves an intermediate layer between the ceramic surface and the redox external agent (liquid or gas phase). The intermediate layer is a multifunctional element and its function depends on the agents involved in redox reaction. The bronze film is formed either on the intermediate layer or in place of it. The initial melt included Na2WO4, WO3, and NaCl. The reticulated ceramic foams, made from pure alumina (Al2O3), were prepared by a standard impregnation method. In all depositions, the temperature was above the melting point of the Na2WO4/WO3 system. The effect of NaCl content on the final coating properties was investigated in the 10–40 mol% range. The best results were obtained with hydrogen reduction of 40% NaCl in the melt. The bronze crystals size in the coating was 0.8–1.6 μm. The bronze layer was continuous throughout the foam. The obtained coating has a bright yellow-gold color, consistent with a stoichiometric parameter value (x) of 0.85–0.95. The resistivity of coated foams decreased from above 12 Ω mm to below 1 Ω mm when the NaCl concentration in the melts increased from 10% to 40%, respectively, due to improved continuity of the bronze crystals. These highly conductive, bronze-coated alumina foams, can potentially serve as high-temperature electrodes in aggressive conditions.

Preparation and Modification of Y2Cu2O5/Y2O3 Photocatalysts for H2 Evolution under Simulated Sunlight Irradiation

2011 ◽  
Vol 239-242 ◽  
pp. 3001-3004 ◽  
Author(s):  
Li Zhang ◽  
Ke Long Huang ◽  
Hao Chen ◽  
Jian Hui Yan
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Production Rate ◽  
Hydrogen Reduction ◽  
Sol Gel ◽  
Oxalic Acid Solution ◽  
Impregnation Method ◽  
Simulated Sunlight ◽  
Hydrogen Production Rate ◽  
Sunlight Irradiation

Y2Cu2O5/Y2O3 (YCO) photocatalysts were prepared using sol-gel method. The photocatalysts were modified by Pt particles to prepare Pt-loaded composite (Pt-YCO) using hydrogen reduction method, and NiO/YCO were synthesized by impregnation method. These obtained samples were characterized by thermogravimetry and differential thermal analysis (TG/DTA), X-ray diffraction (XRD), and ultraviolet visible diffuse reflectance absorption spectra (UV-Vis DRS) techniques. Photocatalytic H2 evolution activity of the modified photocatalysts has been evaluated from aqueous oxalic acid solution used as sacrificial reagent under simulated sunlight irradiation. The result showed that when the concentration of the photocatalysts is 0.8 g·L-1， Pt-YCO photocatalyst exhibits higher photocatalytic activity compared with unloaded YCO. The hydrogen production rate is 4.12 mmol·h-1·g-1 with 1wt% loading amount of Pt, while the loading content is up to 2.5wt%, the hydrogen production rate of Pt-YCO photocatalyst deecreased instead. Whereas NiO/YCO composite exhibits less photocatalytic activity than that of pure YCO under the same conditions.

scholarly journals Adsorption of an Anionic Azo Dye Using Moringa oleifera Seed Protein-Montmorillonite Composite

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao Mi ◽  
Zhenya Shang ◽  
Chunbao Du ◽  
Guoting Li ◽  
Ting Su ◽  
...  
Keyword(s):  
Moringa Oleifera ◽  
Seed Protein ◽  
Freundlich Isotherm ◽  
Water Soluble ◽  
Adoption Process ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Nacl Concentration ◽  
Pseudo Second Order ◽  
Reactive Red 2

In this study, Moringa oleifera seed protein-montmorillonite (MOSP-MMT) composite was synthetized using the impregnation method. The MOSP-MMT adsorbent was characterized using scanning electron microscope, X-ray diffraction, infrared spectroscopy, surface area analysis, and thermogravimetric analysis. The removal of water-soluble reactive red 2 (RR-2) from artificial wastewater by the MOSP-MMT composite was carried out in a batch system. The results indicated that RR-2 adsorption increased with contact time, and the pseudo-second-order equation was best to describe the adoption process among the three models. The RR-2 adsorption decreased from 7.60 to 5.92 mg/g as pH increased from 3.2 to 9.1 and increased from 15.2 to 17.1 mg/g as NaCl concentration increased from 0 to 30 g/L. The Freundlich isotherm model provided the better fit of the experimental data than the Langmuir model. The result showed that the MOSP-MMT composite could be a potential adsorbent for the treatment of wastewater containing RR-2.

Applications of CCEM to Environmental Health Problems

1985 ◽  
Vol 43 ◽  
pp. 102-103
Author(s):  
R. J. Lee ◽  
J. S. Walker
Keyword(s):  
Electron Microscopy ◽  
Image Analysis ◽  
Environmental Health ◽  
Computer Control ◽  
External Agent ◽  
External Agents ◽  
Computer Controlled ◽  
Primitive State ◽  
Textural Changes ◽  
General Aspects

Electron microscopy (EM), with the advent of computer control and image analysis techniques, is rapidly evolving from an interpretative science into a quantitative technique. Electron microscopy is potentially of value in two general aspects of environmental health: exposure and diagnosis.In diagnosis, electron microscopy is essentially an extension of optical microscopy. The goal is to characterize cellular changes induced by external agents. The external agent could be any foreign material, chemicals, or even stress. The use of electron microscopy as a diagnostic tool is well- developed, but computer-controlled electron microscopy (CCEM) has had only limited impact, mainly because it is fairly new and many institutions lack the resources to acquire the capability. In addition, major contributions to diagnosis will come from CCEM only when image analysis (IA) and processing algorithms are developed which allow the morphological and textural changes recognized by experienced medical practioners to be quantified. The application of IA techniques to compare cellular structure is still in a primitive state.

Microstructure of YBa2Cu3O7-x thin films deposited by dc sputtering

1989 ◽  
Vol 47 ◽  
pp. 172-173
Author(s):  
O. Eibl ◽  
G. Gieres ◽  
H. Behner
Keyword(s):  
Thin Films ◽  
Cross Sections ◽  
Intermediate Layer ◽  
Amorphous State ◽  
Critical Currents ◽  
Dc Sputtering ◽  
State Process ◽  
Diffraction Patterns ◽  
Film Substrate ◽  
Substrate Temperatures

The microstructure of high-Tc YBa2Cu3O7-X thin films deposited by DC-sputtering on SrTiO3 substrates was analysed by TEM. Films were either (i) deposited in the amorphous state at substrate temperatures < 450°C and crystallised by a heat treatment at 900°C (process 1) or (ii) deposited at around 740°C in the crystalline state (process 2). Cross sections were prepared for TEM analyses and are especially useful for studying film substrate interdiffusion (fig.1). Films deposited in process 1 were polycristalline and the grain size was approximately 200 nm. Films were porous and the size of voids was approximately 100 nm. Between the SrTiO3 substrate and the YBa2Cu3Ox film a densly grown crystalline intermediate layer approximately 150 nm thick covered the SrTiO3 substrate. EDX microanalyses showed that the layer consisted of Sr, Ba and Ti, however, did not contain Y and Cu. Crystallites of the layer were carefully tilted in the microscope and diffraction patterns were obtained in five different poles for every crystallite. These patterns were consistent with the phase (Ba1-XSrx)2TiO4. The intermediate layer was most likely formed during the annealing at 900°C. Its formation can be understood as a diffusion of Ba from the amorphously deposited film into the substrate and diffusion of Sr from the substrate into the film. Between the intermediate layer and the surface of the film the film consisted of YBa2Cu3O7-x grains. Films prepared in process 1 had Tc(R=0) close to 90 K, however, critical currents were as low as jc = 104A/cm2 at 77 K.

Synthesis and Magnetic Properties of Nanocrystalline Fe-Ni Alloys During Hydrogen Reduction of NiFe2O4

2011 ◽  
Vol 49 (01) ◽  
pp. 52-57 ◽  
Author(s):  
Min Kyu Paek ◽  
Kyung Hyo Do ◽  
Mohamed Bahgat ◽  
Jong Jin Pak
Keyword(s):  
Magnetic Properties ◽  
Hydrogen Reduction ◽  
Ni Alloys

Tunnel Magnetoresistance Effect for Double Tunnel Junctions with Al Intermediate Layer.

2001 ◽  
Vol 25 (4−2) ◽  
pp. 767-770 ◽  
Author(s):  
T. Daibou ◽  
M. Oogane ◽  
Y. Ando ◽  
C. Kim ◽  
O. Song ◽  
...  
Keyword(s):  
Intermediate Layer ◽  
Tunnel Junctions ◽  
Magnetoresistance Effect ◽  
Tunnel Magnetoresistance

Conversion of fructose into methyl lactate over SnO2/Al2O3 catalystin flow regime

2020 ◽  
pp. 43-47
Author(s):  
S.V. Prudius ◽  
◽  
N.L. Hes ◽  
A.M. Mylin ◽  
V.V. Brei ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Practical Interest ◽  
Dimethyl Acetal ◽  
Racemic Mixture ◽  
Process Conditions ◽  
Impregnation Method ◽  
Aqueous Methanol ◽  
Methyl Lactate ◽  
Al2o3 Catalyst ◽  
Target Reaction

In recent years, numerous researchers have focused on the development of catalytic methods for processing of biomass-derived sugars into alkyl lactates, which are widely used as non-toxic solvents and are the starting material for obtaining monomeric lactide. In this work, the transformation of fructose into methyl lactate on Sn-containing catalyst in the flow reactor that may be of practical interest was studied. The supported Sn-containing catalyst was ob-tained by a simple impregnation method of granular γ-Al2O3. The catalytic ex-periments were performed in a flow reactor at temperatures of 160-190 °C and pressure of 3.0 MPa. The 1.6-9.5 wt.% fructose solutions in 80% aqueous methanol were used as a reaction mixture. It was found that addition to a reac-tion mixture of 0.03 wt.% potassium carbonate leads to the increase in selec-tivity towards methyl lactate on 15% at 100% conversion of fructose. Prod-ucts of the target reaction С6Н12О6 + 2СН3ОН = 2С4Н8О3 + 2Н2О were ana-lyzed using 13C NMR method. The following process conditions for obtaining of 65 mol% methyl lactate yield at 100% fructose conversion were found: use of 4.8 wt.% fructose solution in 80% methanol, 180 °С, 3.0 МПа and a load on catalyst 1.5 mmol C6H12O6/mlcat/h at contact time of 11 minutes. The cata-lyst productivity is 2.0 mmol C4H8O3/mlcat/h and the by-productі are 1,3-dihydroxyacetone dimethyl acetal (20%) and 5-hydroxymethylfurfural (10%). It should be noted that a racemic mixture of L- and D-methyl lactates has been obtained by conversion of D-fructose on the SnO2/Al2O3 catalyst. The SnO2/Al2O3 catalyst was found to be stable for 6 h while maintaining full fruc-tose conversion at 55–70% methyl lactate selectivity. After regeneration the catalyst completely restores the initial activity.

Epitaxial Growth of Sr0.3Ba0.7Nb2O6 Thin Films Prepared by Sol-Gel Process

1999 ◽  
Vol 606 ◽  
Author(s):  
Keishi Nishio ◽  
Jirawat Thongrueng ◽  
Yuichi Watanabe ◽  
Toshio Tsuchiya
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Epitaxial Growth ◽  
Raw Materials ◽  
Substrate Surface ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Monomethyl Ether ◽  
Tetragonal Tungsten Bronze ◽  
Sol Gel Process

AbstructWe succeeded in the preparation of strontium-barium niobate (Sr0.3Ba0.7Nb2O6 : SBN30)that have a tetragonal tungsten bronze type structure thin films on SrTiO3 (100), STO, or La doped SrTiO3 (100), LSTO, single crystal substrates by a spin coating process. LSTO substrate can be used for electrode. A homogeneous coating solution was prepared with Sr and Ba acetates and Nb(OEt)5 as raw materials, and acetic acid and diethylene glycol monomethyl ether as solvents. The coating thin films were sintered at temperature from 700 to 1000°C for 10 min in air. It was confirmed that the thin films on STO substrate sintered above 700°C were in the epitaxial growth because the 16 diffraction spots were observed on the pole figure using (121) reflection. The <130> and <310> direction of the thin film on STO were oriented with the c-axis in parallel to the substrate surface. However, the diffraction spots of thin film on LSTO substrate sintered at 700°C were corresponds to the expected pattern for (110).

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