A powder that has it all

A new, efficient procedure for powder coating lowers energy consumption by up to 90% compared to conventional oven processes and offers additional advantages beyond that.

Many industrial applications (such as those in machine and automobile construction) are characterized by high friction and wear while having the highest requirements regarding temperature load and corrosion resistance. This frequently necessitates the use of special coatings, known as tribological coatings. High-performance polymers are especially predestined for such applications. With its high-performance powder material PEEK  (polyetheretherketone), the chemical company Evonik has created the basis for a coating that, due to its very high mechanical, thermal, and chemical resistance, is optimally suited for the requirements described above and can be applied with a completely new production procedure. Conventional coating processes normally entail multiple steps: a chemical component cleaning and a pretreatment
of the part using blast media, a layer application in powder form with a material loss of up to 70%, and a subsequent energy-intensive oven process. In that process, the entire component is typically heated to 400°C to melt the coating material and thus maintain an adherent coating. With the new, laser-based melting procedure, adherent PEEK layers can be produced and characterized on aluminum and steel, both with PEEK powder and with dispersions. The central innovation content of this new procedure consists of the significant improvement of the energy efficiency,

since merely the coating material and a thin edge layer of the component is heated using laser radiation. Calculations show a reduced energy consumption of up to 90% compared to oven processes, depending on the size of the component and the coating surface. Moreover, the material loss is sustainably reduced in the layer application and the pretreatment using blast media, and the chemical component cleaning are omitted thanks to the laser pretreatment. This means metallic components such as pistons or bearing shells in internal combustion engines, metal components in AC compressors, heating surfaces in food production, and small devices such as the traditional waffle iron can be coated in the future.
The new procedure is the result of a collaboration between the companies BECHEM, Clean-Lasersysteme, Evonik, and Fraunhofer ILT in the conclusion of the research project “Enlapro” funded by the state government of North Rhine-Westphalia and the European Union.*
Based on VESTAKEEP PEEK by Evonik, BECHEM produces a water-based PEEK dispersion as a necessary condition for using dipping, printing, and spraying procedures (without electrostatic spraying). It is well known that no other company throughout Germany can produce stable PEEK dispersions in various viscosities

* Project partners of the project funded by funds from the European Fund for Regional Development (Funding Code: EFRE-0801268) comprise the companies Carl Bechem GmbH, Hagen (development of PEEK coatings), Clean-Lasersysteme GmbH, Herzogenrath (laser pretreatment), and the Fraunhofer Institute for Laser Technology ILT, Aachen (laser process development).

Expert knowledge

Dipl.-Chem. (FH) Florian Paland
Head of R+D Anti-Friction Coatings