Kepla-coat

KEPLA-COAT® is a white coloured, plasma chemical coating that improves aluminium and titanium alloys. The coating has high corrosion resistance and excellent abrasion resistance.

KEPLA-COAT® layers applied to aluminium consist of up to 60 percent of corundum. The remaining layer components are mainly Al2O3 and boehmite. Depending on the alloy of the coated workpiece, KEPLA-COAT® can reach a thickness of up to 150 μm. KEPLA-COAT® provides not only excellent wear protection, but also perfect uniform layer, dimensional accuracy and hardness. KEPLA-COAT®-coated substrates have a high fatigue strength. These layers can resist aggressive gases such as chlorine and boron trichloride and a layer thickness of 30 μm, for instance, shows a corrosion resistance of more than 3,000 hours in the salt fog test according to DIN EN ISO 9227. In addition, KEPLA-COAT® ensures extremely good anti-friction properties in combination with PTFE or other dry lubricants.

KEPLA-COAT®-coated aluminum components have a wide variety of applications, including geometrically high-precision rotors in turbo molecular pumps. In this case, the component coating layer, being without any cracks or pores, prevents the infiltration of reaction gases and it provides the necessary protection for plasma etching processes while resisting the mechanical stress generated by the extremely high rotation speed. KEPLA-COAT®-coated aluminum components are used, among other things, as sealing gaskets, fixing discs, cylinders, drums or cylindrical tubes.

Coating takes place in a saline solution electrolyte. The component is connected in series to an external source of electricity and acts as an anode. During anodization oxygen plasma discharges itself on the component 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 component. 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 component treatments such as, for instance, paintwork or impregnation.

KEPLA-COAT® Black can be used to coat all commonly used aluminium- and titanium-based materials. The coating has high light absorption and increases the heat conductivity. The usual layer thickness values lie within the 5 to 15 μm range for aluminium-based materials and at 50 μm for titanium-based materials. Owing to the layer’s crystalline structure the base material’s fatigue strength is only slightly affected. KEPLA-COAT® Black is suitable for optical components, high-precision screw threads or heating radiators. This coating is used in sectors like vacuum technology, microelectronics and the aviation and space industry.