All-Russian Institute of Aviation Materials of the State Science Centre of the Russian Federation, Moscow, Russia:

V. A. Duyunova, Head of Research Department “Titanium, Magnesium, Beryllium and Aluminium Alloys”
I. A. Kozlov, Lead Engineer at the Laboratory for Corrosion and Protection of Metallic Materials, e-mail: lab7@viam.ru
V. A. Kuznetsova, Head of Sector at the Laboratory of Paint and Coatings
А. А. Kozlova, Head of Paint and Coatings Laboratory

The authors conducted a comparative analysis of non-metallic non-organic coatings and their performance in combination with the organosilicon system of the paint coating. The structure of the protective coatings was analysed with the help of scanning electron microscopy, which helped identify and analyse the structural changes occurring in the coatings. The study that looked at the effect of heat on the paint adhesion to ML10 magnesium alloy specimens with different surfaces provided an opportunity to evaluate the interaction between different layers within a protective coating system. An electrochemical study conducted on specimens with protective coatings in a 3% aqueous solution of sodium chloride by impedance spectroscopy provided a quantitative analysis of the coating degradation. The following comparative accelerated salt fog test provided a quality analysis that verified the outcomes of the electrochemical study. The authors describe a mechanism of structural degradation of non-metallic non-organic and paint coatings for the ML10 alloy following a long-term exposure while demonstrating a relationship between the protective ability of the coating and its structure. The authors make an assumption that a long-term exposure at 300 ^oC may trigger thermochemical transformations in both nonmetallic non-organic coatings and paint coatings which create through pores and thus affect the protective ability of the coatings. It was established that, out of the corrosion protection options in view, the best insulating properties are provided by the coating system that employs electrolytic plasma oxidation, which was first used as a surface preparation technique for the ML10 magnesium alloy before it was coated with organosilicon paint.
This research was carried out as part of the complex scientific problems 17.1. “Environmentally friendly electrolytic plasma coatings for light alloys”.

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