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The effect of electrolyte composition on the plasma electrolyte oxidation and phase composition of oxide ceramic coatings formed on 2024 aluminium alloy

Posuvailo V. M., Kulyk V. V., Duriagina Z. A., Koval’chuck I. V., Student M. M., Vasyliv B. D.

Archives of Materials Science and Engineering

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2020

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Vol. 105, nr 2

49--55

EN

Purpose: Purpose of this work is to analyse the process of synthesis of oxide ceramic coatings in plasma electrolytes on 2024 aluminium alloy and to form an electrolyte which allows to reduce energy consumption for the coating formation. Design/methodology/approach: The oxide ceramic coatings were synthesized on 2024 aluminium alloy. The coatings were formed by the alternate application of anode and cathode pulses to the sample. X-ray diffraction analysis of coatings was performed on a DRON-3.0 X-ray diffractometer using CuKa radiation. The thickness of the coatings was determined using a CHY TG-05 thickness gauge. The porosity of the coatings was investigated by analysing the micrographs of the plasma electrolyte oxidation (PEO) coatings obtained on a scanning electron microscope at x500 magnification using the image processing technique. Findings: The electrolyte with 5 g/l H2O2 additive have been elaborated as an optimal composition for synthesis of a coating with an increased content of corundum (a-Al2O3) as compared to a coating synthesized in the same mode in the 3KOH+2Na2SiO3 electrolyte without H2O2. This synthesis mode allows obtaining a coating with a high corundum content at low energy consumption. Research limitations/implications: For further optimization of the synthesis modes, it is necessary to analyse the influence of the phase composition and porosity of the obtained oxide ceramic coatings on their microhardness, wear resistance, and corrosion resistance. Practical implications: Based on the developed modes of synthesis of the coatings, it will be possible to obtain wear and corrosion resistant oxide ceramic coatings with predetermined functional properties and to reduce energy consumption for their formation. Originality/value: Methods for accelerating the formation of coatings have been proposed and tested, in particular, by adding various amounts of hydrogen peroxide to the electrolyte. The content of oxides in the obtained coatings, in particular, their ratios at various concentrations of hydrogen peroxide in the electrolyte, were determined by X-ray phase analysis. The modes of synthesis of the coatings were developed which allow obtaining a continuous coating without cracks with simultaneous decreasing porosity from 4.32% to 3.55-3.53%.

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Druty rdzeniowe serii FMI do natryskiwania łukowego

Pokhmurskyy W. I., Student M. M., Hwozdetskyy W. M., Pokhmurska H. W.

Przegląd Spawalnictwa

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2013

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R. 85, nr 7

6--10

PL

W artykule podano krótki opis opracowanych w Fizyczno-Mechanicznym Instytucie im. G.W. Karpienki Państwowej Akademii Nauk we Lwowie (FMI) drutów proszkowych (DP) do natryskiwania łukowego. Pokazano, że opracowanie i zastosowanie specjalnych drutów rdzeniowych (DR) jako materiałów elektrodowych poszerzyło zastosowanie elektrometalizacji. W wielu przypadkach pozwoliło to na uzyskanie powłok o właściwościach na poziomie najlepszych powłok natryskiwanych innymi metodami natryskiwania cieplnego, na przykład metodą plazmową albo naddźwiękową, przy zachowaniu znacznej przewagi ekonomicznej.

EN

In the present review of the brief description developed in G.V. Karpenko Physico-Mechanical Institute of National Academy of Sciences of Ukraine (FMI) arc spray wires. It is shown that development and using of new special arc spray wires as electrode materials, expanded of electrometallization applications. In many cases, it is possible to obtain a coating having the same characteristics as a top-level spray coatings obtained by using of other thermal spraying methods, e.g., plasma or supersonic methods, while maintaining economic advantages.

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Electrochemical properties of arc sprayed coatings from cored wires on the basis of cheap ferroalloys

Pokhmurskyy W. I., Student M. M., Chervinska N. R., Stupnytskyy T. R., Pokhmurska H. W.

Ochrona przed Korozją

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2013

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nr 11

516--518

EN

Two arc sprayed coatings from cored wires with content of chromium more than 13% have been investigated. Chemical microheterogeneity was determined by the method of a sliding drop in two different media: aqueous MEH solution (0.045% H2SO4 + 0.14% H2O2 + 5•10-5% K2Cr2O7) and 3% NaCl. It was found that heterogeneity and corrosion resistance of arc sprayed coatings depend not only on Cr content, but also on the amount of self-fluxed alloying elements and elements what form the low-melt eutectics in cored wires. Investigated coatings made of cored wires 140Cr17Ni and 140Cr14Ni4Al slightly shift the surface stationary electrode potentials in more positive direction in comparison with steel St.3, and significantly increase their corrosion resistance.

PL

Badano dwie powłoki napylane łukowo z drutów rdzeniowych (CW) z zawartością chromu powyżej 13%. Niejednorodność chemiczna była określona metodą ślizgającej się kropli w dwóch środowiskach: MEH i 3% NaCl. Prąd korozyjny wyznaczano z krzywych polaryzacji. Wykazano, że niejednorodność i opór korozyjny pokryć zależą nie tylko od stężenia Cr, ale również od zawartości samożużlujących się pierwiastków stopowych i pierwiastków, które tworzą niskotopliwe eutektyki w drutach rdzeniowych. Potencjał korozyjny powłok CW1 i CW2 był nieco bardziej dodatni niż potencjał stali St3. Powłoki te znacznie zwiększają odporność korozyjną stali St3.