scholarly journals Electrochemical deposition of cobalt alloy

2021 ◽  
pp. 55-60
Author(s):  
Tetiana Nenastina ◽  
Мykola Sakhnenko ◽  
Valeria Proskurina ◽  
Alla Korohodska ◽  
Natalia Horokhivska
Keyword(s):  
Current Density ◽  
Vanadium Content ◽  
Internal Stresses ◽  
Cobalt Alloys ◽  
Cobalt Alloy ◽  
High Quality ◽  
Wide Range ◽  
Citrate Electrolyte ◽  
Optimal Current ◽  
A Current

Electrodeposition of cobalt alloys with refractory metals makes it possible to obtain coatings with a unique combination of physicochemical properties that are unattainable using other deposition methods. For the deposition of high-quality coatings with a cobalt-vanadium alloy, it is proposed to use a citrate electrolyte. Co-V coating was deposited on steel samples from citrate electrolyte at a temperature of 35-40 °C and a current density of 5-12 A/dm2 using soluble cobalt anodes. The vanadium content in the coating deposited at a ligand concentration of 0.3 mol / dm3 is 0.1-0.5 wt%. An increase in the concentration of the ligand to 0.4 mol / dm3 promotes the binding of cobalt into complexes, and, accordingly, the vanadium content in the coating increases to 0.6-1.2 wt.%. Moreover, the tendency to change the percentage of alloying elements with current density remains. Deposition coatings are dense, shiny, without internal stresses and cracks. The proposed compositions of electrolytes and modes of deposition of Co-V coatings with a vanadium content of up to 1.5 wt.% And a current efficiency of 50%. It was found that Co-V coatings are characterized by increased carbon content and are substitutional solid solutions, and the surface morphology of the obtained coatings depends significantly on the current density and changes from fine-crystalline to globular spheroid. The optimal current density for obtaining high-quality coatings with a cobalt alloy in a galvanostatic mode is ік = 10 A / dm2. Management of the storage of galvanic cobalt alloys in a quite wide range of concentrations of alloy-forming components is achieved by varying the electrolysis parameters, which allows the deposition technology to be adapted to the needs of the modern market.

High-quality epitaxial NbN/AlN/NbN tunnel junctions with a wide range of current density

2013 ◽  
Vol 102 (14) ◽  
pp. 142604 ◽  
Author(s):  
Z. Wang ◽  
H. Terai ◽  
W. Qiu ◽  
K. Makise ◽  
Y. Uzawa ◽  
...  
Keyword(s):  
Current Density ◽  
Tunnel Junctions ◽  
High Quality ◽  
Wide Range

scholarly journals Flexible diamond-like carbon film prepared by hydrothermal electrochemical method

2017 ◽  
Vol 35 (3) ◽  
pp. 447-453
Author(s):  
Ying Tao ◽  
Danqin Yi ◽  
Baojun Zhu ◽  
Wenpeng Cao
Keyword(s):  
Current Density ◽  
Electrochemical Method ◽  
Carbon Film ◽  
Reflectance Spectroscopy ◽  
Internal Stresses ◽  
Diamond Like Carbon ◽  
One Step ◽  
Hydrothermal Electrochemical Method ◽  
A Current

AbstractDiamond-like carbon (DLC) thin films were prepared by hydrothermal electrochemical method in one-step process. The structural characterization of these films was carried out by scanning electron microscopy (SEM), Raman spectroscopy, and infrared reflectance spectroscopy (IR). It was found that there was an increased sp2 carbon content but decreased sp3 carbon and hydrogen contents with an increase in current density. The flexibility and internal stresses of the DLC films were affected by hydrogen, sp3 amorphous carbon and ordered crystalline sp2 carbon contents. The highly flexible DLC films with high sp3 carbon and hydrogen contents were prepared at a current density of 0.001 mA/cm2.

Influence of Process Parameters on Pulse Electroforming of Nickel-Rich Nickel-Cobalt Alloys from Sulfamate Electrolyte

2013 ◽  
Vol 641-642 ◽  
pp. 440-443 ◽  
Author(s):  
Hong You Li ◽  
Ming Ming Yu ◽  
Yi Wang ◽  
Mao Lin Shi
Keyword(s):  
Current Density ◽  
Duty Cycle ◽  
Bath Temperature ◽  
Pulse Frequency ◽  
Industrial Applications ◽  
Cobalt Alloys ◽  
Average Current Density ◽  
Influence Of Process Parameters ◽  
Nickel Cobalt ◽  
Wide Range

Nickel-cobalt alloys have a wide range of industrial applications because of high strength, good corrosion resistance, heat-conductive, etc. As an example, they are used in the electroforming of moulds for die-casting and plastics and in electrotyping. In this paper, experiments on pulse electroforming of nickel-rich nickel-cobalt alloys were studied on SUS304 substrates from sulfamate electrolyte with different average current density, pulse frequency, duty cycle and different bath temperature. It is clearly observed in the nickel-rich deposits that effect of cobalt content gradually increases as the Co2+/Ni2+ concentration ratio and duty cycle increasing; The Co content seems to hardly change when pulse frequency changed from 500 Hz to 1000 Hz; The Co content decreases as current density increasing. High Co content and smooth surface topography can be obtained by reducing current density, increasing bath temperature and pulse duty cycle.

scholarly journals Параметры туннельного барьера сверхпроводниковых структур на основе ниобия

2020 ◽  
Vol 62 (9) ◽  
pp. 1370
Author(s):  
М.Е. Парамонов ◽  
Л.В. Филиппенко ◽  
П.Н. Дмитриев ◽  
М.Ю. Фоминский ◽  
А.Б. Ермаков ◽  
...  
Keyword(s):  
Current Density ◽  
Josephson Junctions ◽  
Quality Parameter ◽  
Tunnel Barrier ◽  
Insulation Layer ◽  
Tunneling Barrier ◽  
Wide Range ◽  
Current Densities ◽  
A Current

The main parameters of the tunneling barrier of the Josephson junctions Nb/AlO<sub>x</sub>/Nb and Nb/AlN/Nb were estimated using the Simmons method in a wide range of current densities. The dependences of the height and width of the tunnel barrier on the resistivity for each type of junctions are experimentally determined. A decrease in the height of the AlN tunnel barrier by 0.3 eV, compared with the oxide one, makes it possible to obtain junctions with a current density above 15 kA/cm<sup>2</sup> at a technologically achievable insulation layer of the order of 10 Angstroms, which makes it possible to realize the quality parameter R<sub>j</sub>/R<sub>n</sub> not lower than 25.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

Theoretical study of the prestressing strand's stress by computer modeling methods

2020 ◽  
Vol 76 (11) ◽  
pp. 1139-1148
Author(s):  
A. G. Korchunov ◽  
E. M. Medvedeva ◽  
E. M. Golubchik
Keyword(s):  
Residual Stresses ◽  
High Strength ◽  
Pearlitic Steel ◽  
Internal Stresses ◽  
Steel Microstructure ◽  
Compressive Stresses ◽  
Wide Range ◽  
Prestressing Strands ◽  
Increasing Temperature ◽  
Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

AMPCOLOY 570

Alloy Digest ◽  
1980 ◽  
Vol 29 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
Iron Alloy ◽  
Heat Treating ◽  
Nickel Aluminum ◽  
High Quality ◽  
Glass Making ◽  
Temperature Performance ◽  
Wide Range ◽  
Cobalt Iron

Abstract AMPCOLOY 570 is a cast copper-nickel-aluminum-cobalt-iron alloy specially developed for applications involving severe stresses and high temperatures, such as glass-making molds and plate-glass rolls. It is significantly superior to cast iron which has been commonly used for glass-making molds. Good foundry techniques will yield high-quality castings of Ampcoloy 570 in a wide range of section sizes. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Cu-392. Producer or source: Ampco Metal Inc..

Real-Time Tem Studies of Electromigration in Submicron Aluminum Runners

1995 ◽  
Vol 391 ◽  
Author(s):  
S. P. Riege ◽  
A. W. Hunt ◽  
J. A. Prybyla
Keyword(s):  
Real Time ◽  
Joule Heating ◽  
Current Density ◽  
Constant Voltage ◽  
Sample Design ◽  
A Current

AbstractDirect real-time observations of electromigration (EM) in submicron Al interconnects were made using a special sample-stage which allowed TEM observations to be recorded while simultaneously heating and passing current through the sample. The samples consisted of 4000 Å thick Al(0.5wt%Cu) patterned over a TEM-transparent window into five runners in parallel, with linewidths 0.2, 0.3, 0.5, 0.8, and 1.0 μm. Both passivated and unpassivated samples were examined. A current density of 2 x 106A/cm2 was used with temperatures ranging from 200 - 350°C. The experiments were done using constant voltage testing, and we used a special sample design which dramatically minimized Joule-heating. Our approach has allowed us to directly observe voids form, grow, migrate, pin, fail a runner, and heal, all with respect to the detailed local microstructure of the runners.

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