Microarc synthesis of nanostructured radiation-absorbing coatings on aluminum and titanium surfaces

Баранова, Т. А.; Chubenko, A. K.; Ryabikov, A. E.; Mamaev, A. I.; Мамаева, В. А.; Beletskaya, E. Yu.

doi:10.1088/1757-899x/286/1/012037

Cited by 5 publications

(2 citation statements)

References 2 publications

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“…The resulting coatings are often hard, dense, crystalline, and well adhered to the metal substrate. They show promise as advanced antifriction materials, wear- , and corrosion-resistant − materials, supports and active components of catalytic systems, − thermal management interfaces, − electrically insulating and optically active layers, , magnetic shielding, , and so forth.…”

Section: Introductionmentioning

confidence: 99%

Relaxation Kinetics of Plasma Electrolytic Oxidation Coated Al Electrode: Insight into the Role of Negative Current

2020

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Plasma electrolytic oxidation (PEO) is an advanced coating process based on high-voltage anodizing. Notwithstanding the anodic nature of the PEO process, it is known that negative polarization leads to synergetic effects in oxide formation efficiency and characteristics of resulting coatings. In this work, we used dynamic anodic voltammograms derived from polarization signal, combining working and diagnostic segments to evaluate in real time the effects of negative polarization on the formation of PEO on the coating on Al in the bipolar regime with a frequency of 50 Hz and a negative-to-positive charge ratio of 1.3. It was found that the hysteresis between ascending and descending branches of the voltammogram can be both caused by prior cathodic polarization and spontaneously generated under unpolarized conditions. This indicated the existence of a quasi-equilibrium in the chemical state of the coating material, which could be perturbed by the external bipolar polarization. The characteristic relaxation time for this system was found to be 40–370 ms. The quasi-equilibrium was attributed to a reversible hydration/dehydration reaction taking place in the active zone of anodic alumina layer (degree of hydration: 10–40%). Coating response analysis via kinetic hydration model allowed both explanations to be provided to a number of previous experimental observations and practical recommendations to be made for the design of efficient electrical regimes for intelligent PEO processes. The latter includes recommendations on avoiding long pauses during negative to positive switching.

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Section: Introductionmentioning

confidence: 99%

Relaxation Kinetics of Plasma Electrolytic Oxidation Coated Al Electrode: Insight into the Role of Negative Current

2020

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“…The breakdowns (also known as "microdischarges"), accompanying the reaction of electrochemical substrate oxidation, transform amorphous deposited film into crystalline forms, as well as provide sintering and densification of the coating materials. Such coatings have perspective applications as antifriction and wear-resistive materials [4,5], anticorrosion protection [6][7][8][9], support for catalysts [10,11], bio-active [12], decorative [13][14][15], thermal barriers [16], electric insulating [17] layers, optical active coatings [18,19], magnetic shielding enclosures [20,21], etc. Unlike conventional anodising, a typical electrolyte solution for PEO does not include any mineral acids or heavy metals, it is normally a dilute solution (0.1-5 wt.%) of alkali, borate, aluminate, silicate, carbonate, phosphate, etc.…”

Section: Introductionmentioning

confidence: 99%

Smart Arbitrary Waveform Generator with Digital Feedback Control for High-Voltage Electrochemistry

Rogov¹

2019

Instruments

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This paper describes a design approach to a control system of power supply for high-voltage electrochemical processes such as plasma electrolytic oxidation (PEO) or high-voltage anodising (HVA), which require alternating polarisation pulses up to 750 V and a typical current density of 50–500 mA/cm2. Complex characteristics of the electrochemical system response on applied polarisations (positive or negative) cause necessity of precise control of polarising pulse shapes for better process operation and its understanding. A device performs cycle-by-cycle pulse-width modulation (PWM) control, including feedback based on digital analysis of the instantaneous current and/or voltage output, and the desired pulse waveform stored in memory for each output polarity. The output stage has four states corresponding to positive or negative pulses, as well as open- or short-circuit conditions, with respect to an electrochemical cell. A fully programmable controller allows one to generate arbitrary waveforms, as well as their sequences, by means of “regime designer” software. Moreover, a smart feedback system can provide adaptation of the next pulse parameter from analysis of the process prehistory. For instance, this approach allows one to separate main electrochemical process (coating formation) and diagnosis of the phenomenon through introduction of high-voltage triangular voltage sweep pulse within a pause of the main process, which is normally carried out under a current control.

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Heterogeneous Metal Oxide Coatings with Magnetoactive Nickel, Cobalt, and Iron Phases Formed by the Method of Pulsed Microplasma Oxidation for Radiation Absorption in the Middle and Near-IR Regions

et al. 2020

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Microarc synthesis of nanostructured radiation-absorbing coatings on aluminum and titanium surfaces

Cited by 5 publications

References 2 publications

Relaxation Kinetics of Plasma Electrolytic Oxidation Coated Al Electrode: Insight into the Role of Negative Current

Relaxation Kinetics of Plasma Electrolytic Oxidation Coated Al Electrode: Insight into the Role of Negative Current

Smart Arbitrary Waveform Generator with Digital Feedback Control for High-Voltage Electrochemistry

Heterogeneous Metal Oxide Coatings with Magnetoactive Nickel, Cobalt, and Iron Phases Formed by the Method of Pulsed Microplasma Oxidation for Radiation Absorption in the Middle and Near-IR Regions

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