Electrochemical Formation of Oxide Films on the Titanium Alloy of Ti6Al4V in Ethylene Glycol-Water Electrolytes to Produce Bioinert Coatings and Increase the Corrosion Resistance of Medical Implants

2021 ◽  
Vol 1038 ◽  
pp. 77-84
Author(s):  
Olha Smirnova ◽  
Andrej Nikonov ◽  
Yulia Mukhina ◽  
Oleksij Pylypenko
Keyword(s):  
Ethylene Glycol ◽  
Current Density ◽  
Chemical Interaction ◽  
Composite Coatings ◽  
Oxide Films ◽  
Research Data ◽  
Anode Current Density ◽  
Minimum Thickness ◽  
Fluoride Ions ◽  
The Individual

The research data on the specific features of the formation of oxide films on the Ti6Al4V alloy in the ethylene glycol-water electrolytes have been given. The kinetic dependences obtained for the alloy allowed us to establish that the specific features of the formation of oxide films during the electrochemical oxidation of the alloy surface depend on the solution composition and the current density. For the water-to-alcohol ratio of 50:50 the kinetic dependences show the sections that correspond to the formation of the barrier oxide layer and also to the formation of the pores due to the desorption of fluoride ions and the growth of the porous portion of oxide. As the water-to- alcohol ratio is decreased the indicated peculiarities of kinetic dependences are met not so often and do not obey any regularity. The obtained data are explained by the fact that an increase in the portion of the organic component of the solution results in a decreased etching capacity of the electrolyte due to the controlled activity of fluoride ions. The anode current density value has a similar effect on the variation of kinetic dependences. Its effect is explained by that an increase in the alloy oxidation rate results in the fast formation of the surface oxide and the specific features of kinetic curves are concealed. The linear relationship between the formation time of oxide of a minimum thickness for given conditions and the current density is unavailable and it is conditioned by the chemical interaction of the oxide film with electrolyte components. The obtained research data can be used for the formation of the individual bioinert and bioactive coatings for the implants of a medical purpose or for the formation of the matrix used for the production of composite coatings.

scholarly journals Studying the Insulating Properties of Oxide Films Obtained on the Ti6A14V Alloy in Tartaric Acid Solutions Using the Method of Electrochemical Decoration by Copper

2021 ◽  
Vol 15 (4) ◽  
pp. 526-535
Author(s):  
Oleksiy Pylypenko ◽  
◽  
Olga Smirnova ◽  
Olga Skorynina-Pohrebna ◽  
Oleksandr Khoroshev ◽  
...  
Keyword(s):  
Oxide Film ◽  
Tartaric Acid ◽  
Current Density ◽  
Electrolyte Concentration ◽  
Formation Rate ◽  
Oxide Films ◽  
Anode Current Density ◽  
Acid Solutions ◽  
Wide Range ◽  
Polarization Dependences

The investigation data of the formation peculiarities of oxide films on the Ti6A14V alloy in tartaric acid solutions have been given. It is shown that the behavior of alloy forming dependences is conditioned by the anode current density. At ja < 0.5 A∙dm-2 the continuous oxide film is not formed on the alloy surface and the preset value of the final voltage on the cell is not reached. With an increase in ja > 0.5 A∙dm-2, alloy forming dependences show a linear behavior that is indicative of the formation of low porous films. In these conditions, the oxide film formation rate is in direct proportion to the value of ja. The electrochemical oxidation of Ti6A14V alloy in tartaric acid solutions results in the formation of interference-colored oxide films. The oxide film ultimate thickness and color are defined by the preset voltage and are independent of the current density and electrolyte concentration. The isolating properties of obtained films were studied by the way of the cathode polarization of oxidized specimens in the sulfate copper-plating electrolyte. The research done allows us to make a conclusion that electrochemical copper deposition is a convenient tool for the detection of defective spots in oxide films. It is shown that due to the specific features of the reduction kinetics of Cu2+ ions on the oxidized titanium it is reasonable to use for the studies the initial sections of polarization dependences that correspond to ΔE = 0.2–0.25 V. The alloy polarization dependences allow us to establish unavailability of apparent dependences between the oxidation current density, the electrolyte concentration, the cell final voltage value and the polarization that occurs during the Cu2+ ion reduction. The anodic connection of copper-coated specimens conditions the reversible dissolution of a greater portion of the specks of copper deposits. It is indicative of the electron conduction of film defects. The obtained data allow us to vary the electrolysis parameters in a wide range with no significant influence of the treatment mode of Ti6A14V alloy on the quality of oxide coatings.

Influence of anode current density on carbon parasitic reactions during electrolysis

2021 ◽  
Author(s):  
Tongxiang Ma ◽  
Lang Zhao ◽  
Yu Yang ◽  
Liwen Hu ◽  
Shengfu Zhang ◽  
...  
Keyword(s):  
Current Density ◽  
Anode Current Density ◽  
Anode Current

scholarly journals High-quality net shape geometries from additively manufactured parts using closed-loop controlled ablation with ultrashort laser pulses

2020 ◽  
Vol 9 (1-2) ◽  
pp. 101-110 ◽  
Author(s):  
Daniel Holder ◽  
Artur Leis ◽  
Matthias Buser ◽  
Rudolf Weber ◽  
Thomas Graf
Keyword(s):  
Surface Roughness ◽  
Closed Loop ◽  
High Surface ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Minimum Thickness ◽  
High Quality ◽  
Surface Optical ◽  
The Individual ◽  
Ultrashort Laser

AbstractAdditively manufactured parts typically deviate to some extent from the targeted net shape and exhibit high surface roughness due to the size of the powder grains that determines the minimum thickness of the individual slices and due to partially molten powder grains adhering on the surface. Optical coherence tomography (OCT)-based measurements and closed-loop controlled ablation with ultrashort laser pulses were utilized for the precise positioning of the LPBF-generated aluminum parts and for post-processing by selective laser ablation of the excessive material. As a result, high-quality net shape geometries were achieved with surface roughness, and deviation from the targeted net shape geometry reduced by 67% and 63%, respectively.

The Migration of Fluoride Ions in Growing Anodic Oxide Films on Tantalum

1997 ◽  
Vol 144 (2) ◽  
pp. 418-423 ◽  
Author(s):  
K. Shimizu ◽  
K. Kobayashi ◽  
G. E. Thompson ◽  
P. Skeldon ◽  
G. C. Wood
Keyword(s):  
Oxide Films ◽  
Anodic Oxide ◽  
Fluoride Ions ◽  
Anodic Oxide Films

Study on Electrodeposition of Ni-Graphite Composite Coatings in Sulfamate Bath

2010 ◽  
Vol 150-151 ◽  
pp. 1546-1550 ◽  
Author(s):  
Xiang Zhu He ◽  
Xiao Wei Zhang ◽  
Xin Li Zhou ◽  
Zhi Hong Fu
Keyword(s):  
Surface Morphology ◽  
Process Parameters ◽  
Current Density ◽  
Graphite Particle ◽  
Particle Concentration ◽  
Composite Coatings ◽  
Nickel Matrix ◽  
Graphite Composite ◽  
Surface Morphologies ◽  
Sulfamate Bath

This paper presented the composite coatings of nickel with graphite particle on the aluminum substrate using a nickel sulfamate bath. Effects of graphite particle concentration on the surface morphologies of the composite coatings were investigated. The inclusion of graphite particle into metal deposits was dependent on many process parameters, including particle concentration, current density, pH and temperature. Results of SEM and XRD demonstrated that graphite particle had successfully deposited on that nickel matrix; besides, the surface morphology of coatings obtained from sulfamate bath containing 2g/L graphite particle dispersed more uniformly than the ones with higher concentration.

scholarly journals Using playful methods to understand children’s digital literacies

2021 ◽  
Author(s):  
Pekka Mertala
Keyword(s):  
Digital Literacy ◽  
Research Data ◽  
Research Approach ◽  
Research Projects ◽  
Digital Literacies ◽  
Research Project ◽  
Childhood Education ◽  
Context Sensitive ◽  
The Individual ◽  
Meaningful Research

This chapter is the final for Section 3 and in many ways stands as an example of how many of the individual elements presented thus far in the book, can come together in a holistic way. This chapter demonstrates how we can adopt play, make it unique to the project and the children and still arrive at meaningful research data. This chapter describes a research project wherein 3- to 6-year-old Finnish children’s digital literacies were studied and supported via playful methods. The key theses this chapter advocates are:-The use of playful methods in early childhood education (ECE) research is one way to acknowledge and respect the characteristics of the research context.-The ambiguity of play should be acknowledged when planning, conducting, and evaluating playful research projects.-Studying and supporting children’s digital literacies do not always require digital devices.The chapter is structured as follows. First, a reflective discussion on the ambiguity of play and the use of playful methods as a context-sensitive research approach is presented. Then, an overview of the research project and its objectives are provided. In the end, three concrete examples of how the children’s digital literacy was studied and supported using playful methods are given.

scholarly journals Morphology and Hardness of Electrochemically-Codeposited Ti-Dispersed Ni-Matrix Composite Coatings/ Morfologia I Twardość Elektrochemicznie Współosadzonych Powłok Kompozytowych Ni-Ti

2014 ◽  
Vol 59 (4) ◽  
pp. 1287-1292 ◽  
Author(s):  
S. Srikomol ◽  
P. Janetaisong ◽  
Y. Boonyongmaneerat ◽  
R. Techapiesancharoenkij
Keyword(s):  
Matrix Composite ◽  
Current Density ◽  
High Current Density ◽  
Composite Coatings ◽  
Initial Increase ◽  
Particle Loading ◽  
Plating Bath ◽  
Matrix Deformation ◽  
Ti Particles

Abstract The effects of current density and Ti particle loading in a plating bath on the morphology and hardness of Ni-Ti composite coatings via an electrochemical-codeposition process were investigated. The Ti-reinforced Ni-matrix composite coatings were codeposited on copper substrates using a Ni-ion electrolytic solution stably suspended with -45 micron Ti particles. Within the current studied range, the coatings’ Ti contents are in the range between 46 and 62 at.%. The morphology appeared to vary with current density. Structures of the Ni-Ti composite coatings produced under low current density conditions revealed denser structures, which is in contrast to the more porous structures noted in the coatings produced under high current density. An initial increase of current density from 100 to 150 mA/cm2 also tends to raise Ti coating content. The reinforcement of Ti particles in the coatings also increased their hardness, which is attributed to the possible role of the embedded Ti particles in hindering matrix deformation. The effect of Ti loading on the coating’s Ti contents was not significant under conditions used in the present study

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