Effect of Processing Time on the Microarc Oxidation Coatings Produced on Magnesium AZ61 Alloy at Constant Hybrid Voltage

Abstract

MAO ceramic coatings were prepared on AZ61 magnesium alloy for various processing times ranging from 5 to 60 min, in an electrolyte solution based on silicate-fluoride. The mechanical, electrochemical and, microstructural properties and the phase compositions of the coating layers were investigated. In this work, unlike previous studies, coatings with high amounts of the Mag 2 SiO 4 phase were formed which contained small amounts of MgO and MgF 2 at a processing condition of 30 min. A microstructural analysis revealed that the porosity of the coatings was reduced considerably with an increase in the processing time, together with a change in the pore geometry from an irregular to a spherical shape. Potentiodynamic polarization and mechanical testing results showed that the coatings acquired after a processing time of 30 min were superior to all of the others.

Assessment of thermodynamic parameters of the plasma chemical process for magnesium oxide production

“…Beryllium fluoride forms a molten slag with MgF 2 , dissolving beryllium oxide from the surface of the reduced metal particles. At this moment, JSC "Ulba Metallurgical Plant" has accumulated about 2000 tons of magnesium fluoride MgF 2 in beryllium production [11]. Thus, it is an urgent task to recycle magnesium fluoride waste generated at beryllium production during magnesium thermal reduction of beryllium fluoride and to sell magnesium oxide as a commercial product.…”