Control of the Mg alloy biodegradation via PEO and polymer-containing coatings

Highlights: • Functional Ca/P PEO-coating with limited barrier properties is formed on Mg alloy. • PEO-coating is modified with superdispersed polytetrafluoroethylene using EPD. • Coatings decrease corrosion activity of the sample and ensure its biocompatibility. • The protective properties and morphology evolution of samples are examined in MEM. • The mechanism of the corrosion evolution of the coated Mg sample in MEM is revealed. The composite calcium-phosphate coating on MA8 Mg alloy consisting of the inorganic porous basis sealed with polymer is suggested. To control the alloy resorption kinetics, the coating obtained by plasma electrolytic oxidation is modified with superdispersed polytetrafluoroethylene using electrophoretic deposition (EPD). Protective properties and morphology evolution as a result of surface treatment and corrosion propagation are examined by EIS, PDP, hydrogen evolution tests, SEM, EDX and XRD analysis. The obtained coatings are investigated at mechanistic level using SVET and local pH measurements. EPD composite coating decreases electrochemical activity of the sample in minimum essential medium and ensures the material biocompatibility.