Caption of photo: Plane milling head made of Magnesium (AZ91). It is protected against wear and corrosion with a MAGOXID-COAT®.
MAGOXID-COAT® is a plasma chemical coating that improves magnesium alloys.
Coating takes place in a saline solution electrolyte. The workpiece is connected in series to an external source of electricity and acts as an anode. During anodization oxygen plasma discharges itself on the workpiece surface and briefly melts the surface thus forming 2 oxide ceramic layers that bond tightly with the outer metallic layer. A barrier layer with a thickness of about 100 nm constitutes the direct bond with the magnesium workpiece. Then come an oxide ceramic layer with low porosity density followed by one with high porosity density. This layer bond protects the magnesium against wear and corrosion and, thanks to its surface structure, it allows the absorption of lubricants as well as following workpiece treatments such as, for instance, paintwork or impregnation.