Decanoate conversion layer with improved corrosion protection for magnesium alloy

A novel decanoate conversion layer (DCL) with improved hydrophobicity for the corrosion protection of Mg alloy is fabricated and tested. XRD, EDX and FTIR results suggest that DCL comprises (CH3(CH2)8COO)2Mg and Mg(OH)2. The contact angle of DCL increases with increased cycling number and reaches ca. 120° at the 30th cycle. The corrosion protection of DCL is much better than that of a decanoate inhibition layer, and close to that of a chromate conversion layer. With increased thickness, improved compactness and hydrophobicity, the decanoate conversion is proven to be a green and effective way to protect Mg alloys from corrosion.

► A decanoate conversion layer is achieved using cyclic voltammetric method.
► The corrosion protection of the decanoate inhibition layer can be improved greatly.
► The decanoate conversion layer is thicker, more compact with high hydrophobicity.
► The decanoate conversion layer is of environmental friendliness and effectiveness.