Formation mechanism and corrosion resistance of the hydrophobic coating on anodized magnesium

•A biomimetic hydrophobic coating is electrodeposited on anodized magnesium.•The nucleation and growth of coating present two stages during deposition process.•Deposition time affects the morphology and corrosion behavior of the coating.•Coating deposited for 60 min obtains the best corrosion resistance.•Coating deposited for 60 min has higher contact angle and thicker coating.

A hydrophobic coating is electrodeposited on the surface of anodized magnesium. Two stages are observed on the current density vs. time curve during the electrodeposition process. They are related to the nucleation and growth of the coating. The deposition time of the coating affects the morphology, the hydrophobicity and the corrosion behavior of the coated substrate. When the deposition time is 60 min, the best corrosion resistance is obtained. The coating is degradable in the simulated body fluid and the composition of the coating changes from C36H70CaO4 to C36H70CaO4·H2O after immersion.