This is an Open-Access article distributed under the terms of the Creative Commons
Attribution Non-Commercial License which permits unrestricted non-commercial use, distribution, and reproduction in any
medium, provided the original work is properly cited.
Received: June 18, 2019; Revised: September 20, 2019; Accepted: September 20, 2019
Abstract: This paper reviews recent approaches to develop composite polymer-containing coatings by plasma electrolytic oxidation (PEO) using various low-molecular fractions of superdispersed polytetrafluoroethylene (SPTFE). The features of the unique approaches to form the composite polymer-containing coating on the surface of MA8 magnesium alloy were summarized. Improvement in the corrosion and tribological behavior of the polymer-containing coating can be attributed to the morphology and insulating properties of the surface layers and solid lubrication effect of the SPTFE particles. Such multifunctional coatings have high corrosion resistance (Rp = 3.0×107 Ω cm2) and low friction coefficient (0.13) under dry wear conditions. The effect of dispersity and x-potential of the nanoscale materials (ZrO2 and SiO2) used as electrolyte components for the plasma electrolytic oxidation on the composition and properties of the coatings was investigated. Improvement in the protective properties of the coatings with the incorporated nanoparticles was explained by the greater thickness of the protective layer, relatively low porosity, and the presence of narrow non-through pores. The impedance modulus measured at low frequency for the zirconia-containing layer (|Z|f=0.01 Hz = 1.8×106 Ω·cm2) was more than one order of magnitude higher than that of the PEO-coating formed in the nanoparticles-free electrolyte (|Z|f=0.01 Hz = 5.4×104 Ω·cm2).