Corrosion Behavior of Modified Anodic Oxide Coatings on AD31 Aluminium Alloy

The dependences of the protective properties of the anodic oxide coatings on the AD31 aluminum alloy surface modified with nitrates of magnesium, potassium, and some 3 d -elements on the composition of sealing solutions and parameters of finishing treatment were established by scanning electron microscopy, potentiodynamic polarization, electrochemical impedance spectroscopy, and salt spray chamber tests. A mechanism of the formation of modified anodic oxide coatings during sealing and subsequent thermal treating was proposed.