Microarc oxidation coatings and corrosion behavior of 7050 aluminum alloy

Ceramic coatings were formed on 7050 aluminum alloy (AA7050) by microarc oxidation (MAO). Subsequently, scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS) were used to evaluate the microstructure of the coatings. The coatings consist of an outer porous layer made of Al₂O₃ and an inner dense layer made of sintered alumina and aluminum substrate. Furthermore, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) were combined with slow strain rate tests (SSRT) to investigate the effect of microarc oxidation on the corrosion and stress corrosion cracking (SCC) of AA7050 in 3.5% NaCl solution. The corrosion on the surface of AA7050 and the corrosion rate and SCC decrease owing to the coatings on AA7050.