HOW TO MAKE MAGNESIUM ALLOYS BE RESISTANT TO OPERATIONAL RISKS

• Main Authors: N. M. Chigrinova, E. A. Vorobiova, V. E. Chigrinov
• Format: Article
• Language: Russian
• Published: Belarusian National Technical University 2016-09-01
• Series: Nauka i Tehnika
• Subjects: micro-arc oxidation; structure formation; electrolyte; fluorides
• Online Access: https://sat.bntu.by/jour/article/view/952
• ISSN: 2227-1031; 2414-0392

The paper studies regularities and mechanisms of structure and phase formation in the surface layers of magnesium alloys when they are processed by method of micro-arc oxidation [MAO]. It has been determined that the same specific features of structure formation, namely: existence of a thin dense inner sublayer and a thicker outer sublayer with developed porosity are common for all types of coatings on the surface of magnesium and aluminum alloys. Such structural state of a protective coating can not be considered as a guaranteed protection against operational impacts, taking into account the fields of their primary application that is aviation construction, automotive construction, instrumentation, building construction, etc. The paper has analyzed the effect of alkaline electrolytes with varying chemical composition due to additions of sodium fluoride or potassium on the structure and properties of these alloys as well as on the level of basic performance characteristics of the layers formed in such electrolytes. On the basis of the analysis a conclusion has been made that it is possible to extend their life-span under operational conditions. It has been revealed that the existing techniques and methods for process control of MAO aluminum and magnesium alloys, particularly processing modes and technological equipment capacity determine a nature of structure formation and changes in a phase composition of the formed coatings.