Effect of electrolysis regimes on the structure and properties of coatings on aluminum alloys formed by anode­cathode micro arc oxidation

Belozerov, Valery; Sоbоl, O. V.; Mahatilova, Anna; Subbotinа, Valeria; Tabaza, Taha A.; Al-Qawabeha, Ubeidulla F.; Al-Qawabah, Safwan M.

doi:10.15587/1729-4061.2018.121744

Cited by 12 publications

(15 citation statements)

References 20 publications

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“…Therefore, to achieve high hardness and wear resistance of MAO coatings on aluminum alloys, it is necessary to provide a large percentage of the a-A1 2 O 3 (corundum) phase. Moreover, as was established in [31,35], phase formation during the MAO treatment of aluminum alloys in the microarc discharge mode begins with the γ-А1 2 О 3 phase, which undergoes the γ→a transition as the coating forms.…”

Section: Literature Review and Problem Statementmentioning

confidence: 76%

“…The latter was determined by an increase in luminosity. It is known that the properties of MAO coatings (base layer) are primarily determined by their phase composition [31,35].…”

Section: Results Of the Study Of The Influence Of Mao Treatment Regimmentioning

confidence: 99%

“…The work [32] describes the microarc oxidation process for creating an oxide film on the surface of metals and alloys by their anodic polarization in a conducting medium. It was shown that microarc oxidation is accompanied by the formation of microplasma [33] and microregions with high pressure due to the gases formed [34,35]. This leads to the occurrence of high-temperature chemical transformations [36,37] and the transport of substance in the arc [38,39].…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…The presence of direct contact between the metal and the breakdown region allows expecting a large effect of the chemical composition of the aluminum alloy on the properties of coatings [45]. Preliminary studies have shown that the phase composition of coatings on different grades of aluminum alloys is different, which is apparently due to the partial completion of the transformation of the low-temperature modification of γ-A1 2 O 3 alumina into the stable modification a-A1 2 O 3 [31,35].…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

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Determination of influence of electrolyte composition and impurities on the content of -AL2O3 phase in MАO-coatings on aluminum

Subbotinа¹,

Al-Qawabeha²,

Belozerov³

et al. 2019

EEJET

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Методом мікродугового оксидування технічно чистого алюмінію і алюмінію легованого міддю і цинком в лужно-силикатном електроліті при щільності струму ~20 А/дм 2 одержані покриття товщиною близько 100 мкм. Наведено результати дослідження морфології поверхні, фазового складу і твердості МДО-покриттів. Параметрами зміни служили склад електроліту і концентрація легуючих (Cu і Zn) елементів. Це дослідження проведено тому, що наявних в даний час даних не достатньо для уявлення про характер впливу хімічного складу алюмінієвого сплаву і умов електролізу (зокрема, складу електроліту) на механізм і кінетику перетворення γ→a. А без розуміння цього спрямована зміна структурного стану і властивостей МДО покриттів стає неможливою. В результаті досліджень було встановлено, що при мікродуговом оксидуванні алюмінієвих сплавів в лужному електроліті з додаванням рідкого скла (Na 2 SiO 3) різної концентрації зміцнений шар складається з оксидів a-А1 2 О 3 , γ-А1 2 О 3 і муллита 3Al 2 O 3 • 2SiO 2. Дані рентгеноструктурного аналізу покриттів свідчать про кристалічну будову покриттів. Встановлено, що легування алюмінію міддю і цинком істотно впливає на фазовий склад покриття, змінюючи кількісне співвідношення фаз нелінійним чином. Найбільший вміст a-А1 2 О 3 фази (до 60 об. %) досягається при легуванні Cu. При цьому найбільш висока твердість МДО покриттів досягається при використанні електроліту складу 1 г/л KOH і 6 г/л Na 2 SiO 3 в алюмінієвих сплавах при вмісті міді більше 3 %, а цинку-2-3 %. Встановлено, що механізм формування фазового складу слід пов'язати зі стабілізацією і дестабілізацією фази γ-А1 2 О 3. З цього для досягнення високої твердості слід вибирати ті легуючі елементи, які впливають на дестабілізацію γ-А1 2 О 3 , що забезпечує утворення фази a-А1 2 О 3 (корунд). У зв'язку з цим виявлено, що катіони Cu 2+ сприяють дестабілізації фази γ-А1 2 О 3 , а катіони Zn 2+ призводять до стабілізації фази γ-А1 2 О 3 при утриманні Zn>3 % Ключові слова: мікродугове оксидування, анодно-катодний режим, склад електроліту, легування, фазовий склад, корунд

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Section: Literature Review and Problem Statementmentioning

confidence: 76%

“…The latter was determined by an increase in luminosity. It is known that the properties of MAO coatings (base layer) are primarily determined by their phase composition [31,35].…”

Section: Results Of the Study Of The Influence Of Mao Treatment Regimmentioning

confidence: 99%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Section: Literature Review and Problem Statementmentioning

confidence: 99%

See 2 more Smart Citations

Determination of influence of electrolyte composition and impurities on the content of -AL2O3 phase in MАO-coatings on aluminum

Subbotinа¹,

Al-Qawabeha²,

Belozerov³

et al. 2019

EEJET

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“…However, the mechanism of the formation of this phase, due to the complexity and heterogeneity of the MAO process, cannot yet be theoretically predicted. Therefore, to determine the patterns and mechanisms of the formation of the phase-structural state in the MAO process, empirical data are currently used for different technological conditions [36,37]. In this case, as a rule, the phase composition of the coatings changes over the MAO layer thickness [38,39].…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

A study of the phase-structural engineering possibilities of coatings on D16 alloy during micro-arc oxidation in electrolytes of different types

Subbotinа

Sоbоl

Belozerov

et al. 2020

EEJET

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The effect of electrolysis conditions with different electrolyte compositions on the growth kinetics, phase-structural state, and hardness of coatings obtained by microarc oxidation (MAO) on the D16 aluminum alloy (base-aluminum, main impurity Cu) was studied. An analysis of the results obtained showed that the choice of the type of electrolyte and the conditions for the MAO process makes it possible to vary the growth kinetics and phase-structural state of the coating on the D16 aluminum alloy within a wide range. For all types of electrolytes, with an increase in the content of KOH, Na 2 SiO 3 , or KOH+Na 2 SiO 3 , the growth rate of MAO coatings increases. It was found that in MAO coatings obtained in an alkaline (KOH) electrolyte, a two-phase (γ−Al 2 O 3 and α−Al 2 O 3 phases) crystalline state is formed. An increase in the KOH concentration leads to an increase in the relative content of the α-Al 2 O 3 phase (corundum). During the formation in a silicate electrolyte, the phase composition of MAO coatings with an increase in the content of liquid glass (Na 2 SiO 3) changes from a mixture of the γ−Al 2 O 3 phase and mullite (3Al 2 O 3 •2SiO 2) to an X-ray amorphous phase. The use of a complex electrolyte leads to a two-phase state of the coating with a large (compared to an alkaline electrolyte) shift of the γ−Al 2 O 3 →α−Al 2 O 3 transformation towards the formation of the α−Al 2 O 3 phase. It was determined that the value of hardness correlates with the content of the α−Al 2 O 3 phase in the MAO coating, reaching the maximum value of 1620 kg/mm 2 at the highest content (about 80 vol. %) of the α−Al 2 O 3 phase. Two types of dependences of the coating thickness on the amount of electricity passed were revealed. For the amount of passed electricity 10-50 A-h/dm 2 , the thickness dependence is determined as 4.2 µm/(A-h/dm 2), which suggests the basic mechanism of electrochemical oxidation during the formation of a coating. For the amount of electricity transmitted 50-120 A-hour/ dm 2 , the thickness dependence is determined by a much smaller value of 1.1 µm/(A-hour/dm 2). This suggests a transition to a different mechanism of coating formation − the formation of a coating with the participation of electrolysis components

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A review of process characteristics of plasma electrolytic oxidation of aluminium alloy

Jadhav

Bongale

Kumar

2021

J. Phys.: Conf. Ser.

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The Plasma Electrolytic Method of Oxidation (PEMO ) is proved powerful for producing the wear and corrosion-resistant coating of the oxide layer for exclusive applications. This technique is having a better capability for industrial use for growing proactive coatings on material like Aluminium, Magnesium, Titanium for diverse application of lightweight and high temperature requirements applications. The paper consists of review of papers primarily based on the surface modification amendment method of plasma arc oxidation of aluminium and its alloy. Because the process characterized by the discharge generated by electrode, electrolyte composition and oxide coating morphology which might be crucial component for effectiveness of the technique. The purpose of the paper is to write the systematic review for electrodes, electrolyte compositions, and its effect in improving the characteristics of aluminium alloys. There is a large scope for enhancing the method and monitoring the electric parameters of PEMO for massive applications in regions of automotive wherein the modification in surfaces can replace the components by the lightweight aluminium alloy material. The attempt is made to pick the key elements inside the technique. The scope of designing numerous optimization algorithms and analytical modelling is a key area for further research which can help to screen the technique extra precisely to get an optimized coating microstructure.

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Effect of electrolysis regimes on the structure and properties of coatings on aluminum alloys formed by anodecathode micro arc oxidation

Cited by 12 publications

References 20 publications

Determination of influence of electrolyte composition and impurities on the content of -AL2O3 phase in MАO-coatings on aluminum

Determination of influence of electrolyte composition and impurities on the content of -AL2O3 phase in MАO-coatings on aluminum

A study of the phase-structural engineering possibilities of coatings on D16 alloy during micro-arc oxidation in electrolytes of different types

A review of process characteristics of plasma electrolytic oxidation of aluminium alloy

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Effect of electrolysis regimes on the structure and properties of coatings on aluminum alloys formed by anode­cathode micro arc oxidation

Cited by 12 publications

References 20 publications

Determination of influence of electrolyte composition and impurities on the content of -AL2O3 phase in MАO-coatings on aluminum

Determination of influence of electrolyte composition and impurities on the content of -AL2O3 phase in MАO-coatings on aluminum

A study of the phase-structural engineering possibilities of coatings on D16 alloy during micro-arc oxidation in electrolytes of different types

A review of process characteristics of plasma electrolytic oxidation of aluminium alloy

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Effect of electrolysis regimes on the structure and properties of coatings on aluminum alloys formed by anodecathode micro arc oxidation