THE EFFECT OF TANTALUM PENTOXIDE CONTENT IN PEO-COATINGS FOREMED ON MA8 MAGNESIUM ALLOY ON ELECTROCHEMICAL PROPERTIES AND IN VITRO APATITE-FORMING ABILITY

10.25712/ASTU.1811-1416.2024.01.002

Abstract

The paper presents the results of a study of the effect of the concentration of tantalum pentoxide in coatings obtained by plasma electrolytic oxidation (PEO) on their electrochemical properties and on the in vitro apatite-forming ability. According to the results of the analysis of the electrochemical behavior of the coatings in SBF, the impedance modulus of Ta₂O₅-containing PEO-coatings is, on average, more than 2 orders of magnitude higher than the impedance modulus of the uncoated MA8 alloy. An increase in the content of tantalum pentoxide in the composition of the PEO-coatings leads to a decrease in their protective properties. It was found that the first clusters of apatite appear on the surface of the PEO-coating after 1 day of soaking in SBF. After 28 days the PEO-coating is completely covered with a layer of apatite with plate-like morphology. During 21 days of exposure of the Ta₂O₅-containing PEO-coating in SBF, the concentration of Ca²⁺ ions in the solution stabilizes, which is due to the reaching of equilibrium between the medium and formed layer of apatite.