Composite coatings formed by combination of plasma electrolytic oxidation and fluoropolymer spraying: composition, morphology and electrochemical properties. K.V. NADARAIA, D.V. MASHTALYAR, I.M. IMSHINETSKIY, S.L. SINEBRYUKHOV, S.V. GNEDENKOV
Keywords:
magnesium alloys, composite coatings, plasma electrolytic oxidation, spray-coating, superdispersed polytetrafluoroethylene, corrosionAbstract
Composite coatings formed by combination of plasma electrolytic oxidation and fluoropolymer spraying:
composition, morphology and electrochemical properties. *K.V. NADARAIA1, 2, D.V. MASHTALYAR1, 2,
I.M. IMSHINETSKIY1, S.L. SINEBRYUKHOV1, S.V. GNEDENKOV1 ( 1Institute of Chemistry, FEB RAS,
Vladivostok, 2Far Eastern Federal University, Vladivostok). *E-mail: nadaraiakv@mail.ru
Presented a method of the formation of composite polymer-containing coatings on a MA8 magnesium alloy by
combination the method of plasma electrolytic oxidation (PEO) and the subsequent incorporation of superdispersed
polytetrafluoroethylene to the PEO layer from a suspension by spray-coating. The composition of the coatings and their
morphological features were determined by SEM, EDS and XRD analyses. The presented data confirm the embedding
of fluoropolymeric material in the composition of the composite coating based on PEO layer. It is established that
the composite coating consists of magnesium, oxygen, silicon, fluorine, which are components of such compounds as
magnesium oxide, magnesium silicate and polytetrafluoroethylene. The data of potentiodynamic polarization indicate a decrease in the corrosion current density by more than 3 orders of magnitude in comparison with a basic PEO coating. The charge transfer at the coating / electrolyte interface is described by the method of electrochemical impedance spectroscopy. It has shown that composite coatings are highly resistant to long-term exposure a corrosive environment.
