Virtually Maintenance-Free Lightweight Drives
As a lightweight material, magnesium suffers from poor corrosion resistance and low hardness. Materials scientists have now succeeded in using laser beams to melt the high-performance plastic PEEK onto the surface of lightweight components made of magnesium and other metals. The key in this case is that the laser also applies a protective layer to specific areas of the component that are subject to particular stress.
Initial trials show that the applied layer can extend the component’s service life 100-fold in the event of wear due to abrasion. The process has been developed by researchers from ELB – Eloxalwerk Ludwigsburg Helmut Zerrer GmbH – and the Fraunhofer Institute for Laser Technology ILT. Possible applications for the new coating technology include moving parts in engines, motors, gears or bearings, i.e. wherever temperature stability or low friction, and hence low wear, is required.
Protective layer made of high-performance plastic PEEK
To coat a component with the protective layer of the high-performance plastic PEEK, the plastic together with additives is applied to the component precisely. A two-beam laser system then ensures that the PEEK is melted specifically on the treated area. The result is an extremely thin high-performance polymer surface that protects the material against corrosion and abrasion.
The new process offers several advantages: "The targeted use of the laser in a specific area keeps the exposure of heat on the component as low as possible", explains Jörg Zerrer, Managing Director of ELB. In addition, the process is very resource-efficient because no material is "lost" by the targeted application, as, for example, in mist that arises when a protective layer is sprayed on. "Moreover, we do not use any environmentally harmful solvents", Jörg Zerrer affirms.
Longer durability of the protective layer
Initial technical tests show the potential of the new process: the pin on disc test examines frictional behaviour and wear. For this purpose, for example, a steel ball is loaded against a rotating plate coated with the protective layer. In this case, the distance from which wear of the layer can be detected is examined.
"Compared to existing systems on the market, we have been able to reduce friction and wear so much that our new coating lasts 100 times longer. The lower friction ensures higher energy efficiency in operation, for example, with moving components in engine/motor components or bearings, meaning that virtually maintenance-free drives are possible", Jörg Zerrer says. “The new process opens up new fields of application for lightweight materials such as magnesium or aluminium", says Dr. Wolfgang Seeliger, Managing Director of Leichtbau BW GmbH.