Deposition of microarc oxidation-polycaprolactone duplex coating to improve the corrosion resistance of magnesium for biodegradable implants

The present study addresses the deposition of a duplex coating by microarc oxidation (MAO) treatment and polycaprolactone (PCL) coating to improve the corrosion resistance of Mg. A uniform PCL coating layer is formed by dip coating method on MAO treated Mg, and the corrosion resistance of MAO-PCL duplex coated Mg is evaluated by potentiodynamic polarization study and immersion test. The results reveal that the porous nature of MAO treated Mg fails to offer a better corrosion resistance in Hanks' balanced salt solution (HBSS). However, deposition of PCL coating (using 4 and 7 wt.% PCL) over MAO treated Mg significantly increased the corrosion resistance of Mg in HBSS for 7 days. The MAO-PCL duplex coating can be a good alternative method of protecting Mg from rapid corrosion for biodegradable implant applications.