The native film of MgO/Mg(OH)2/MgCO3 formed on the AZ91 magnesium alloy during air exposure has a porous nature and poor adhesion. It not only cannot protect the Mg substrate adequately, but also is sometimes prone to more corrosion reactions. Deposition of a coating is an effective way to enhance the corrosion resistance and in particular, diamond like carbon (DLC) coatings can produce excellent protection and performance due to the low friction and chemical inertness. In some cases, doping with extraneous elements has been observed to enhance the corrosion resistance of DLC coatings and the properties depend on the deposition technique and precursors. In this work, we aim at improving the corrosion resistance and adhesion strength of DLC coatings by producing an intermediate layer before DLC deposition by nitrogen plasma immersion ion implantation and deposition (N-PIII&D).
