scholarly journals Effect of the Electrolyte Temperature and the Current Density on a Layer Microhardness Generated by the Anodic Aluminium Oxidation

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Emil Spišák ◽  
Miroslav Gombár ◽  
Ján Kmec ◽  
Alena Vagaská ◽  
Erika Fechová ◽  
...  
Keyword(s):  
Growth Rate ◽  
Chemical Composition ◽  
Anodic Oxidation ◽  
Current Density ◽  
Vickers Microhardness ◽  
Surface Current ◽  
Oxidation Time ◽  
Electrolyte Temperature ◽  
Current Densities ◽  
Oxalic Acids

The paper investigates the influence of the chemical composition and temperature of electrolyte, the oxidation time, voltage, and the current density on Vickers microhardness of aluminium oxide layers, at the same time. The layers were generated in the electrolytes with different concentrations of sulphuric and oxalic acids and surface current densities 1 A·dm−2, 3 A·dm−2, and 5 A·dm−2. The electrolyte temperature varied from −1.78°C to 45.78°C. The results have showed that while increasing the electrolyte temperature at the current density of 1 A·dm−2, the increase in the layer microhardness values is approximately by 66%. While simultaneously increasing the molar concentration of H2SO4in the electrolyte, the growth rate of the microhardness value decreases. At the current density of 3 A·dm−2, by increasing the electrolyte temperature, a reduction in the microhardness of the generated layer occurs with the anodic oxidation time less than 25 min. The electrolyte temperature is not significant with the changing values of the layer microhardness at voltages less than 10.5 V.

Anodic Oxidation Parameters on Al-Cu Alloy Anodizing Film's Electrochemical Ability by EIS

2006 ◽  
Vol 11-12 ◽  
pp. 665-668
Author(s):  
Chao Guo ◽  
Yu Zuo ◽  
Jing Mao Zhao ◽  
Xu Hui Zhao ◽  
Jin Ping Xiong
Keyword(s):  
Anodic Oxidation ◽  
Porous Layer ◽  
Current Density ◽  
Barrier Layer ◽  
Oxidation Time ◽  
Equivalent Circuits ◽  
Anodic Current Density ◽  
Anodic Current ◽  
Cu Alloy ◽  
Oxidation Parameters

EIS is used in this paper to study the effects of anodic oxidation parameters on the film’s ability, and multi-layer equivalent circuits are proposed. The oxidation time has great effect on porous layer, the porous layer’s impedance increases as the anodic oxidation time prolong; anodic current density has effect on both barrier layer and porous layer, higher current density gets higher impedance values in both barrier layer and porous layer; anodic oxidation temperature has great effect on barrier layer, when the temperature decreases, the barrier layer’s impedance increases.

Titanium Dioxide (TiO2) Films by Anodic Oxidation in Phosphoric Acid

2012 ◽  
Vol 545 ◽  
pp. 223-228 ◽  
Author(s):  
Hasan Zuhudi Abdullah ◽  
Charles Christopher Sorrell
Keyword(s):  
Phosphoric Acid ◽  
Anodic Oxidation ◽  
Current Density ◽  
Room Temperature ◽  
Single Phase ◽  
Microstructural Characteristics ◽  
Laser Raman ◽  
Acid Bath ◽  
Current Densities ◽  
Electrical Bias

Anodic oxidation is an electrochemical method for the production of an oxide film on a metallic substrate. It involves the application of an electrical bias at relatively low currents while the substrate is immersed in an acid bath. The films can be very dense and stable, with a variety of microstructural characteristics. In the present work, films of the anatase polymorph of TiO2were formed on high-purity Ti foil (50 μm thickness) using phosphoric acid (0.3 M H3PO4). The conditions of oxidation involved the application of potentials (5 to 350 V) and current densities (5 to 60 mA.cm-2) for 10 min at room temperature. The films were characterised using a digital photography, laser Raman microspectroscopy, and field emission scanning electron microscopy. The thicknesses of the oxide films on Ti were measured using a thin film analyser based on optical spectroscopy principles. The colours, thicknesses, and microstructures of the films depended strongly on the applied voltage and current density. At bias more than 15 V, single-phase anatase was observed to form on Ti at low (5 mA.cm-2) and higher (up to 60 mA.cm-2) current density.

Jet Electrodeposited Cu-Al2O3 Nanocomposite Coatings

2007 ◽  
Author(s):  
Jin-Song Chen ◽  
Yin-Hui Huang ◽  
Zhi-Dong Liu ◽  
Zong-Jun Tian
Keyword(s):  
Current Density ◽  
Cathodic Current Density ◽  
Nanocomposite Coatings ◽  
Electrolyte Temperature ◽  
Cathodic Current ◽  
Electrodeposited Coatings ◽  
Jet Electrodeposition ◽  
Current Densities ◽  
Jet Velocity ◽  
Electrolyte Jet

A jet electrodeposition device was carried out to prepare Cu-Al2O3 nanocomposite coatings. The influence of the concentration of Al2O3 in the electrolyte and parameters, such as cathodic current density, the electrolyte temperature as well as the electrolyte jet velocity, on the content of the Al2O3 in the deposite were investigated. The coatings ingredient and microstructure was measured by the scanning electron microscope (SEM) with energy dispersive analyzer system (EDX), the microhardness tests were conducted on an microhardness tester. The results show that the jet electrodeposition can fine crystalline particles. The copper deposited layers have nanocrystalline microstructure with grain size of about 50nm. The amount of Al2O3 in composites first increased and then decreased with an increase in the concentration of Al2O3, current density, temperature and jet velocity. The composite with optimum atomic percent of Al2O3 (14.4 at%) can be obtained at the concentration of 30 g/l, cathodic current densities 300 A/dm2, temperature 30°C, and electrolyte jet velocity 8 m/s. The addition of Al2O3 in copper increases the microhardness of the electrodeposited coatings.

Preparation and properties of the anodized film on Fe-Cr-Al alloy surface

2020 ◽  
Vol 67 (4) ◽  
pp. 379-386
Author(s):  
Jialin Yang ◽  
Yunting Guo ◽  
Wei Zai ◽  
Siyuan Ma ◽  
Liang Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ethylene Glycol ◽  
Anodic Oxidation ◽  
Current Density ◽  
Oxidation Process ◽  
Electrochemical Impedance ◽  
Oxidation Mechanism ◽  
Oxidation Time ◽  
Al Alloy ◽  
Content Type

Purpose This paper aims to find a way to improve the surface insulation, corrosion resistance and mechanical properties of Fe-Cr-Al electrothermal alloy, exploring the best oxidation condition and analyzing the oxidation mechanism. Design/methodology/approach Electrochemical workstation was used for anodic oxidation, and the effect of current density, ethylene glycol concentration and oxidation time on properties of the film were investigated by resistivity test, scanning electron microscope, electrochemical tests (potentiodynamic polarization and electrochemical impedance spectroscopy) and mechanical tests, and the oxidation process was analyzed by X-ray photoelectron spectroscopy (XPS). Findings According to the potential-time curves of anodic oxidation and the analysis of XPS, the whole oxidation process can be divided into four stages. When the current density is 0.8 A/dm2, the ethylene glycol concentration is 10%, and the oxidation time is 60 min, the film has the best corrosion protection, mechanical properties and surface morphology. The resistivity of the samples is about 13 orders magnitude than that of the matrix. Originality/value In this paper, a protective electrically insulating film was prepared by anodic oxidation in an alkaline electrolyte solution. The oxidation conditions were optimized and the oxidation mechanism was analyzed.

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.

Electron-beam damage of oxides at high current densities

1989 ◽  
Vol 47 ◽  
pp. 634-635
Author(s):  
M. R. McCartney ◽  
J. K. Weiss ◽  
David J. Smith
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Current Density ◽  
Transition Metal Oxides ◽  
Time Resolved ◽  
Rapid Acquisition ◽  
Resolution Electron ◽  
Current Densities ◽  
Electron Stimulated Desorption ◽  
Channel Analyzer

It is well-known that electron-beam irradiation within the electron microscope can induce a variety of surface reactions. In the particular case of maximally-valent transition-metal oxides (TMO), which are susceptible to electron-stimulated desorption (ESD) of oxygen, it is apparent that the final reduced product depends, amongst other things, upon the ionicity of the original oxide, the energy and current density of the incident electrons, and the residual microscope vacuum. For example, when TMO are irradiated in a high-resolution electron microscope (HREM) at current densities of 5-50 A/cm2, epitaxial layers of the monoxide phase are found. In contrast, when these oxides are exposed to the extreme current density probe of an EM equipped with a field emission gun (FEG), the irradiated area has been reported to develop either holes or regions almost completely depleted of oxygen. ’ In this paper, we describe the responses of three TMO (WO3, V2O5 and TiO2) when irradiated by the focussed probe of a Philips 400ST FEG TEM, also equipped with a Gatan 666 Parallel Electron Energy Loss Spectrometer (P-EELS). The multi-channel analyzer of the spectrometer was modified to take advantage of the extremely rapid acquisition capabilities of the P-EELS to obtain time-resolved spectra of the oxides during the irradiation period. After irradiation, the specimens were immediately removed to a JEM-4000EX HREM for imaging of the damaged regions.

scholarly journals Effect of Plating Current Density on the Ball-On-Disc Wear of Sn-Plated Ni Coatings on Cu Foils

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 56
Author(s):  
Ashutosh Sharma ◽  
Byungmin Ahn
Keyword(s):  
Current Density ◽  
Wear Loss ◽  
Wear Properties ◽  
Friction Behavior ◽  
Track Geometry ◽  
Cu Substrates ◽  
Current Densities ◽  
The Impact ◽  
Sliding Distance ◽  
Ball On Disc

Metallic and alloyed coatings are used widely in several decorative and technology-based applications. In this work, we selected Sn coatings plated on Cu substrates for joining applications. We employed two different plating baths for the fabrication of Sn and Ni coatings: acidic stannous sulfate for Sn and Watts bath for Ni layer. The plating current densities were varied from 100–500 mA/cm2. Further, the wear and friction behavior of the coatings were studied using a ball-on-disc apparatus under dry sliding conditions. The impact of current density was studied on the morphology, wear, and coefficient of friction (COF) of the resultant coatings. The wear experiments were done at various loads from 2–10 N. The sliding distance was fixed to 7 m. The wear loss was quantified in terms of the volume of the track geometry (width and depth of the tracks). The results indicate that current density has an important role in tailoring the composition and morphology of coatings, which affects the wear properties. At higher loads (8–10 N), Sn coatings on Ni/Cu had higher volume loss with a stable COF due to a mixed adhesive and oxidative type of wear mechanism.

Thermal Parameters, Microstructure and Porosity During Transient Solidification of Ternary Al–Cu–Si Alloys

2012 ◽  
Vol 730-732 ◽  
pp. 883-888 ◽  
Author(s):  
Daniel J. Moutinho ◽  
Laércio G. Gomes ◽  
Otávio L. Rocha ◽  
Ivaldo L. Ferreira ◽  
Amauri Garcia
Keyword(s):  
Growth Rate ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Tip Growth ◽  
Thermal Parameters ◽  
Volumetric Fraction ◽  
Dendritic Network ◽  
Intermetallic Particles ◽  
Casting Length

Solidification of ternary Al-Cu-Si alloys begins with the development of a complex dendritic network typified by primary (λ1) and secondary (λ2) dendrite arm spacings which depend on the chemical composition of the alloy and on the casting thermal parameters such as the growth rate and the cooling rate. These thermal parameters control the scale of dendritic arms, the size and distribution of porosity and intermetallic particles in the casting. In this paper, λ1and λ2were correlated with experimental thermal parameters i.e., the tip growth rate and the tip cooling rate. The porosity profile along the casting length has also been experimentally determined. The volumetric fraction of pores increase with the increase in alloying Si and with the increase in Fe concentration at the regions close to the casting cooled surface.

Sign in / Sign up

Export Citation Format

Share Document