Caption of the photo: Geometrically high-precision rotors made of AlMgSi1 and coated with KEPLA-COAT® that is fitted to turbo molecular pumps used in plasma-etching processes
KEPLA-COAT® is a plasma chemical coating that improves aluminium and titanium 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 aluminium or titanium workpiece. Then come an oxide ceramic layer with low porosity density followed by one with high porosity density. This layer bond protects the aluminium and titanium 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.