Institute of Сhemistry of Far Eastern Branch of Russian Academy of Sciences, Vladivostok, Russia:

S. L. Sinebryukhov, Assistant Professor, Head of Laboratory of Non-stationary Surface Processes
A. S. Gnedenkov, Junior Researcher, e-mail: asg17@mail.com
D. V. Mashtalyar, Senior Researcher, Laboratory of Biomedical Composite Coatings
S. V. Gnedenkov, Professor, Deputy Director for Science, Head of Department of Electrochemical Systems and Surface Modification Processes

This article offers a method of formation of self-healing coating, which electrochemical properties are detaily described. This coating is obtained on the surface of magnesium alloys, using plasma electrolytic oxidation method and further inhibitor-filling of created layer. Methods of scanning vibration probe and scanning ion-selective electrode (as local scanning electrochemical surface research methods) were used for definition of kinetics and self-healing mechanism, and for investigation of inhibitor ability to suppress the corrosion process during formation of defect, made by scratch-testing method. Obtained data point the significantly bigger dissolution rate of sample with defect in the basic plasma electrolythic oxidation layer, in comparison with the sample with self-healing inhibitor-containing coating on the surface. Processing of plasma electrolytic oxidation coating by corrosion process inhibiting 8-oxyquinoline solution provides the 30-time increasing of coating protection characteristics in the conditions of environmental corrosion attack, and prevents the intensive material damage. Results analysis points the corrosion process of successful deceleration by inhibitor even after a week of alloy exposure in corrosion-active environment. According to this, developed method provides the obtaining of self-healingcapable coating during its exploitation in corrosion-active solution. Self-healing mechanism was researched and described. Environmental corrosion attack is continuously suppressed by 8-oxyquinoline (included into the coating), due to which, corrosion keeps the low rate during the long term of exploitation of composite coating magnesium alloy.

This work was carried out with the support of Russian Scientific fund (No. 14-33-00009) and the Government of Russian Federation (Federal agency of scientific organizations).

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