Dynamic model of single discharge during microarc oxidation

Нечаев, Г. Г.; Popova, S.

doi:10.1134/s0040579515040338

Cited by 11 publications

(6 citation statements)

References 7 publications

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“…The observed morphology is similar to the structure with a well-known mechanism of the formation and collapse of the vapor-gas and plasma bubbles in the channels of micro-arc discharges described in the work [ 40 , 41 , 42 ]. The occurrence of micro-discharge during MAO is due to the formation of a vapor-gas bubble pore due to the heating of the oxide layer at the substrate’s interface.…”

Section: Resultssupporting

confidence: 81%

“…The surface morphology of the coatings is represented by the spheroidal elements (spheres and hemispheres) with the characteristic open pores and local particulates (Figure 3a-c,g-i). The observed morphology is similar to the structure with a well-known mechanism of the formation and collapse of the vapor-gas and plasma bubbles in the channels of micro-arc discharges described in the work [40][41][42]. The occurrence of micro-discharge during MAO is due to the formation of a vapor-gas bubble pore due to the heating of the oxide layer at the substrate's interface.…”

Section: Morphology and Topography Characterizationsupporting

confidence: 78%

“…The occurrence of micro-discharge during MAO is due to the formation of a vapor-gas bubble pore due to the heating of the oxide layer at the substrate's interface. After an electric breakdown, the vapor-gas bubble transforms into a plasma bubble with a simultaneous formation of a discharge channel (pore) as a natural to keep away the heated electrolyte The observed morphology is similar to the structure with a well-known mechanism of the formation and collapse of the vapor-gas and plasma bubbles in the channels of micro-arc discharges described in the work [40][41][42]. The occurrence of micro-discharge during MAO is due to the formation of a vapor-gas bubble pore due to the heating of the oxide layer at the substrate's interface.…”

Section: Morphology and Topography Characterizationsupporting

confidence: 55%

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Zn- or Cu-Containing CaP-Based Coatings Formed by Micro-arc Oxidation on Titanium and Ti-40Nb Alloy: Part I—Microstructure, Composition and Properties

et al. 2020

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Zn- and Cu-containing CaP-based coatings, obtained by micro-arc oxidation process, were deposited on substrates made of pure titanium (Ti) and novel Ti-40Nb alloy. The microstructure, phase, and elemental composition, as well as physicochemical and mechanical properties, were examined for unmodified CaP and Zn- or Cu-containing CaP coatings, in relation to the applied voltage that was varied in the range from 200 to 350 V. The unmodified CaP coatings on both types of substrates had mainly an amorphous microstructure with a minimal content of the CaHPO4 phase for all applied voltages. The CaP coatings modified with Zn or Cu had a range from amorphous to nano- and microcrystalline structure that contained micro-sized CaHPO4 and Ca(H2PO4)2·H2O phases, as well as nano-sized β-Ca2P2O7, CaHPO4, TiO2, and Nb2O5 phases. The crystallinity of the formed coatings increased in the following order: CaP/TiNb < Zn-CaP/TiNb < Cu-CaP/TiNb < CaP/Ti < Zn-CaP/Ti < Cu-CaP/Ti. The increase in the applied voltage led to a linear increase in thickness, roughness, and porosity of all types of coatings, unlike adhesive strength that was inversely proportional to an increase in the applied voltage. The increase in the applied voltage did not affect the Zn or Cu concentration (~0.4 at%), but led to an increase in the Ca/P atomic ratio from 0.3 to 0.7.

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Section: Resultssupporting

confidence: 81%

Section: Morphology and Topography Characterizationsupporting

confidence: 78%

Section: Morphology and Topography Characterizationsupporting

confidence: 55%

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Zn- or Cu-Containing CaP-Based Coatings Formed by Micro-arc Oxidation on Titanium and Ti-40Nb Alloy: Part I—Microstructure, Composition and Properties

et al. 2020

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“…Spherical formations (bubbles) can be seen in the coating deposited at 500 V, in the field of the intense micro-arc discharge output. This "boiling" of the coating substance [60,61] is due to the melting of electrolyte components and the formation of the melt. SEM images of the cross-sections of the coatings show that the coatings have a loose porous structure (Figure 3c,f).…”

Section: Morphology Structure and Elemental Composition Of The W-coatingsmentioning

confidence: 99%

Surface Modification of Mg0.8Ca Alloy via Wollastonite Micro-Arc Coatings: Significant Improvement in Corrosion Resistance

Sedelnikova

Ugodchikova

Толкачева

et al. 2021

Metals

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Biodegradable materials are currently attracting the attention of scientists as materials for implants in reconstructive medicine. At the same time, ceramics based on calcium silicates are promising materials for bone recovery, because Ca2+ and Si2+ ions are necessary for the mineralization process, and they take an active part in the formation of apatite. In the presented research, the protective silicate biocoatings on a Mg0.8Ca alloy were formed by means of the micro-arc oxidation method, and the study of their morphology, structure, phase composition, corrosion, and biological properties was carried out. Elongated crystals and pores were uniformly distributed over the surface of the coatings. The coated samples exhibited remarkable anti-corrosion properties in comparison with bare magnesium alloy because their corrosion current decreased 10 times, and their corrosion resistance increased almost 100 times. The coatings did not significantly affect the viability of the cells, even without the additional dilution of the extract, and were non-toxic according to ISO 10993-5: 2009. In this case, there was a significant difference in toxicity of the pure Mg0.8Ca alloy and the coated samples. Thus, the results demonstrated that the applied coatings significantly reduced the toxicity of the alloy.

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“…Among various surface treatment methods, plasma electrolytic oxidation (PEO) has the advantages of a strong strengthening effect, non-pollution, and simple process [3][4][5]. However, the plasma discharge process of magnesium alloy involves a complex combination of physical processes, chemical reactions and electrochemical reactions [6][7][8]. Equivalent circuit modelling simplifies complex systems and represents the load characteristics of the system in the form of a circuit [9,10].…”

Section: Introductionmentioning

confidence: 99%

In-situ estimate of coating by equivalent circuit for PEO of AZ31B

Wang

Liu

et al. 2023

Surface Engineering

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The paper discusses an in-situ estimated methodology of coating using the equivalent circuit for the plasma electrolytic oxidation (PEO) process. An equivalent circuit of the second-order nonlinear structure can be proposed from the transient load waveform and the arc image recorded during pulsed bipolar PEO treatment. The transfer function of the linear part of the model was derived from Kirchhoff's law and Laplace's transformation rule; the nonlinear part of the model was fitted using Fitting Theory. Then the calculation method of each element value was derived in the equivalent circuit. The characterisation results of the coating properties show that the changes of different element values by the equivalent circuit can reflect the changes in coating thickness, coating density and discharge intensity. The relationship between the values of several elements and the microstructure of the coating is analysed comprehensively; a prediction method for the corrosion resistance of the coating is provided.

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Dynamic model of single discharge during microarc oxidation

Cited by 11 publications

References 7 publications

Zn- or Cu-Containing CaP-Based Coatings Formed by Micro-arc Oxidation on Titanium and Ti-40Nb Alloy: Part I—Microstructure, Composition and Properties

Zn- or Cu-Containing CaP-Based Coatings Formed by Micro-arc Oxidation on Titanium and Ti-40Nb Alloy: Part I—Microstructure, Composition and Properties

Surface Modification of Mg0.8Ca Alloy via Wollastonite Micro-Arc Coatings: Significant Improvement in Corrosion Resistance

In-situ estimate of coating by equivalent circuit for PEO of AZ31B

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