A chemical conversion coating is provided. The chemical conversion coating is disposed on a surface of a magnesium alloy substrate.  The chemical conversion coating contains manganese, magnesium, oxygen, and cerium, wherein a content of magnesium in the chemical conversion coating is between 10 at% to 20 at%, and a content of cerium in the chemical conversion coating is between 5 at% to 10 at%. As follows:

• A novel route in strongly acidic KMnO₄ solution in our study.


• Prepared a relatively-compact KMnO₄ conversion coating on Mg alloy.


• Our coating exhibited a better corrosion resistance than the chromate coated.


• The coating could reduce the corrosion area to approximately 3% after 72 h SST.


• A conversion coating with self-healing function on magnesium alloy.