New features of surface modification of magnesium alloys by microarc oxidation (MAO)

The work investigates the features of forming M & Acy;O coatings on magnesium alloys. It is shown that due to the choice of electrolysis conditions (electrolyte composition, current density and oxidation time) the process of microarc oxidation in the microarc discharge mode is stably implemented. It has been established that as a result of M & Acy;O treatment, ceramic coatings containing phases of magnesium oxide MgO, spinel MgAl2O4, Mg2SiO4 and Mg-3(& Rcy;& Ocy;(4))(2) are formed. The phase composition of the coatings is determined by the composition of the electrolyte. The electrolysis conditions studied in this work provide high hardness of the coatings, reaching 7500 MPa, as well as high corrosion resistance. The obtained results allow us to recommend M & Acy;O coatings obtained on magnesium alloys both as an outer (functional) layer with high adhesion to the substrate and as a sublayer for the subsequent application of protective coatings (varnishes, polymers, in particular polytetrafluoroethylene).