Structure–property control of MAO coatings on pure magnesium in a Ca/P/Si/Cu-containing electrolyte via voltage and current

Micro-arc oxidation (MAO) was applied to pure magnesium to form multifunctional oxide coatings in a Ca/P/Si/Cu-containing electrolyte using different applied voltages (300–400 V) and current levels (180–280 mA). The influence of electrical parameters on coating morphology, topography, thickness, mechanical properties, adhesion, wettability, surface free energy, as well as chemical and phase compositions was systematically investigated. Increasing voltage promoted coating growth, development of porous surface structures, and enhanced incorporation of electrolyte-derived elements. The results demonstrate that voltage control, in particular, enables the effective tailoring of MAO coating structure and properties, highlighting the biomaterial potential of the obtained coatings.