Electrodeposition and the Optimization of Molybdenum Layer on Nb-Ti-Si Based Ultra-High Alloys from Aqueous Solution

2018 ◽  
Vol 913 ◽  
pp. 396-405
Author(s):  
Gao Yue ◽  
Xi Ping Guo
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Surface Morphology ◽  
Cross Section ◽  
Low Oxygen ◽  
Applied Current ◽  
Molybdenum Coating ◽  
Applied Current Density ◽  
Epma Analysis ◽  
Substrate Ph

Depositing a molybdenum layer through electrodeposition is a possible and economical way to prepare Mo layer. It could be a new preparation of MoSi2coating on Nb-Ti-Si based alloys combined with halide pack cementation. In this paper, the effects of pre-coated Re layer on the substrate, pH of the electrolyte, water to acetate ratio and the applied current density on the deposition were investigated and optimized to obtain low oxygen content, adherent molybdenum coating on Nb-Ti-Si based alloys. The surface morphology and cross section were characterized by SEM. The thickness of the deposit is about 6 μm and nodules and cracks were observed on the surface. EDS and EPMA analysis suggested the presence of Mo and its oxides in the deposit; XPS results confirmed the presence of Mo, Mo2O3and MoO3in the as-deposited layer. The crystal structure of as-prepared coating was amorphous by the XRD investigation, and the metallic molybdenum was the main existence form of the molybdenum element in the deposit.

Electrochemical degradation of 4-chlorophenol in aqueous solution using modified PbO2 anode

2012 ◽  
Vol 66 (11) ◽  
pp. 2468-2474 ◽  
Author(s):  
X. Y. Duan ◽  
F. Ma ◽  
L. M. Chang
Keyword(s):  
Aqueous Solution ◽  
Electrochemical Oxidation ◽  
Current Density ◽  
Supporting Electrolyte ◽  
Positive Influence ◽  
Applied Current ◽  
Applied Current Density ◽  
Toc Removal ◽  
First Order Kinetics ◽  
Pbo2 Electrode

The electrochemical oxidation of 4-chlorophenol (4-CP) in aqueous solution was studied by electrochemical oxidation using modified PbO2 electrode as anode. The influence of several operating parameters, such as initial 4-CP concentration, applied current density, and supporting electrolyte (Na2SO4) concentration was investigated. Ultraviolet spectroscopy and total organic carbon (TOC) measurements were conducted to study the kinetics of 4-CP electrochemical reaction and the mineralization efficiency of 4-CP. The experimental results showed that the 4-CP degradation always followed a pseudo-first-order kinetics. The higher mineralization of 4-CP and the lower current efficiency (CE) were obtained by the lower initial 4-CP concentration. The applied current density showed a positive influence on the degradation of 4-CP and the removal of TOC, but a higher applied current density led to a lower CE. Although Na2SO4 concentration of 0.05 M resulted in a higher 4-CP and TOC removal, the result of one-way analysis of variance (ANOVA) indicates that Na2SO4 concentration is not the significant parameter for 4-CP removal in electrochemical oxidation.

Investigation on Morphology and Microstructure of the SALD SiC

1998 ◽  
Vol 542 ◽  
Author(s):  
Lianchao Sun ◽  
James E. Crocker ◽  
Leon L. Shaw ◽  
Harris L. Marcus
Keyword(s):  
Crystal Structure ◽  
Silicon Carbide ◽  
Surface Morphology ◽  
Cross Section ◽  
Target Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
The Cross

AbstractIn this work, the deposition of silicon carbide lines using a tetramethylsilane (TMS) precursor was investigated. Effects of target temperatures on the morphology and crystal structure of the deposits were examined. It was found that the morphology of the SALD SiC depends strongly on the target temperature. The contour of the cross section of the SiC deposits changes from a triangle to trapezoid to volcano shape and the surface morphology of the deposited lines changes from smooth to rough to porous as the target temperature increases. A critical target temperature was found to be about 700°C to initiate deposition of SiC under the current experimental configurations. X-ray diffraction analyses show that the SALD SiC formed at 1000°C contains both crystalline and amorphous phases. The results are briefly discussed.

scholarly journals Synthesis, Crystal Structure, Hydrogen Bonding and Thermal Behaviour of a Three-Dimensional Cu(II)-benzene-1,2,4,5-tetracarboxylate Templated by 1,9-Diaminononane

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Water Molecules ◽  
Excess Charge ◽  
Gauche Conformation ◽  
Coordination Polyhedra ◽  
Thermoanalytical Measurements

Triclinic single crystals of Cu4(H3N–(CH2)9–NH3)(OH)2[C6H2(COO)4]2·5H2O were preparedin aqueous solution at 80 °C in the presence of 1,9-diaminononane. Space group P-1 (no. 2)with a = 1057.5(2), b = 1166.0(2), c = 1576.7(2) pm, alpha = 106.080(10)°, beta = 90.73(2)° and gamma =94.050(10)°. The four crystallographic independent Cu2+ ions are surrounded by five oxygenatoms each with Cu–O distances between 191.4(3) and 231.7(4) pm. The connection betweenthe Cu2+ coordination polyhedra and the [C6H2(COO)4]4–anions yields three-dimensionalframework with negative excess charge and wide centrosymmetric channel-like voids. Thesevoids extend parallel to [001] with the diagonal of the nearly rectangular cross-section ofapproximately 900 pm. The channels of the framework accommodate [H3N–(CH2)9–NH3]2+cations and water molecules, which are not connected to Cu2+. The nonane-1,9-diammoniumcations adopt a partial gauche conformation. Thermoanalytical measurements in air show aloss of water of crystallization starting at 90 °C and finishing at approx. 170 °C. Thedehydrated compound is

ФОРМИРОВАНИЕ ПЕРЕХОДНОГО СЛОЯ ALN НА ТЕМПЛЕЙТАХ 3С-SIC/SI(111) МЕТОДОМ АММИАЧНОЙ МОЛЕКУЛЯРНО-ЛУЧЕВОЙ ЭПИТАКСИИ

2020 ◽  
Vol 96 (3s) ◽  
pp. 148-153
Author(s):  
С.Д. Федотов ◽  
А.В. Бабаев ◽  
В.Н. Стаценко ◽  
К.А. Царик ◽  
В.К. Неволин
Keyword(s):  
Crystal Structure ◽  
Growth Rate ◽  
Low Temperature ◽  
Surface Morphology ◽  
Single Crystal ◽  
Root Mean Square Roughness ◽  
Rate Variation ◽  
Mean Square ◽  
Nucleation Layer ◽  
Low Temperature Epitaxy

Представлены результаты изучения морфологии поверхности и структуры слоев AlN, сформированных аммиачной МЛЭ на темплейтах 3C-SiC/Si(111) on-axis- и 4° off-axis-разориентации. Опробован технологический режим низкотемпературной эпитаксии зародышевого слоя AlN на поверхности 3C-SiC(111). Среднеквадратичная шероховатость поверхности (5 х 5 мкм) слоев AlN толщиной 150 ± 50 нм составила 2,5-3,5 нм на темплейтах 3C-SiC/Si(111) on-axis и 3,3-3,5 нм на 4° off-axis. Показано уменьшение шероховатости смачивающего слоя AlN при изменении скорости роста. Получены монокристаллические слои AlN(0002) со значениями FWHM (ω-геометрия) 1,4-1,6°. The paper presents the surface morphology and crystal structure of AlN layers formed by ammonia MBE on 3C-SiC/Si(111) on-axis and 4° off-axis disorientation. It offers the technological approach of low-temperature epitaxy of the AlN nucleation layer on the 3C-SiC (111) surface. Root mean square roughness (5 х 5 |xm) of AlN layers with thickness of 150 ± 50 nm was 2,5-3,5 nm onto on-axis templates and 3.3-3.5 nm onto 4° off-axis. It appears that the RMS roughness of the AlN surface is changing with the growth rate variation. Single-crystal AlN(0002) layers with FWHM values (ω-geometry) of 1.4-1.6° have been obtained.

scholarly journals Fabrication of Transparent Mg(OH)2 Thin Films by Drop-Dry Deposition

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 724
Author(s):  
Tong Li ◽  
Masaya Ichimura
Keyword(s):  
Thin Films ◽  
Aqueous Solution ◽  
Optical Properties ◽  
Surface Morphology ◽  
Magnesium Hydroxide ◽  
Dry Deposition ◽  
Visible Range ◽  
Substrate Heating ◽  
Water Effects ◽  
Deposition Conditions

Magnesium hydroxide (Mg(OH)2) thin films were deposited by the drop-dry deposition (DDD) method using an aqueous solution containing Mg(NO3)2 and NaOH. DDD was performed by dropping the solution on a substrate, heating-drying, and rinsing in water. Effects of different deposition conditions on the surface morphology and optical properties of Mg(OH)2 thin films were researched. Films with a thickness of 1−2 μm were successfully deposited, and the Raman peaks of Mg(OH)2 were observed for them. Their transmittance in the visible range was 95% or more, and the bandgap was about 5.8 eV. It was found that the thin films have resistivity of the order of 105 Ωcm. Thus, the transparent and semiconducting Mg(OH)2 thin films were successfully prepared by DDD.

Unusual π-π interactions directed by [{(C6H6)Ru}2W8O30(OH)2]6– hybrid anion

CrystEngComm ◽  
2021 ◽  
Author(s):  
Anna A Mukhacheva ◽  
Vladislav Komarov ◽  
Vasily Kokovkin ◽  
Alexander S. Novikov ◽  
Pavel A Abramov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Building Block ◽  
Π Interactions

The [{(C6H6)Ru}2W8O30(OH)2]6– hybrid (organometallic-POM) anion was used as a pH-tunable building block to create special conditions for realizing π-π interactions in the crystal structure. Changing pH of aqueous solution of...

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