Ecologically safe modified solutions for deposition of conversion coatings on steel
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- Category: Geotechnical and mining mechanical engineering, machine building
- Last Updated on 07 January 2019
- Published on 26 December 2018
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Authors:
S.V.Frolenkova, Cand. Sc. (Tech.), orcid.org/0000-0002-6727-2903, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
V.I.Vorobyova, Cand. Sc. (Tech.), orcid.org/0000-0001-7479-9140, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
T.A.Overchenko, Cand. Sc. (Tech.), orcid.org/0000-0002-5883-6228, National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
M.I.Skiba, Cand. Sc. (Tech.), orcid.org/0000-0001-9686-736X, Ukrainian State University of Chemical Technology, Dnipro, Ukraine, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Abstract:
Purpose. To analyze the impact of the nature of solution components on the process of conversion coating formation on low-carbon steel.
Methodology. Coatings were obtained by exposing samples to the modifying solution at an ambient temperature for certain time. The potentiostatic and potentiodynamic polarization were employed to investigate solution components’ impact on the steel surface behavior. Conversion film content was determined with an X-ray microscope. Pictures of the obtained coatings were derived with optical and electron microscopes. The obtained conversion coatings corrosion protection efficiency was determined by the gravimetric measurements.
Findings. A number of cold solutions for the formation of modified oxide conversion coatings on low-carbon steel for temporary protection against corrosion in liquid and air environments have been elaborated. As a basis for such mixtures, zinc acetate solutions are proposed. As modifying additives oxoanions were used whose incorporation into oxide conversion films was confirmed by X-ray scanning microscopy. It was determined that the holding time increase leads to a rise in content of modifying components in the film and growth of its thickness.
Originality. The elaborated solution compositions make it possible to form stable oxide films of different composition, such as conversion coatings on steel at room temperatures. These oxide conversion coatings are resistant to corrosion in the majority of aggressive liquid and aerated environments. The applied environmental-friendly components shift the metal substrate into a passive state, providing additional corrosion resistance. The protective oxide coat is formed as a result of reduction of modifying additives on the surface of the metal to the form of oxygen-containing compounds.
Practical value. The proposed safe conversion solutions are an alternative to ecologically hazardous chromium-containing mixtures holding their own protective effect compared to known organic inhibitors, but do not require complicated synthesis. The developed modified solutions also exclude the energy component during obtaining conversion coatings that leads to simplification of hardware design and cheapening of technological process of their obtaining.
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