Nanoscale boundary layers
- Landesstiftung BW
- Forschungszentrum Jülich
Gearboxes, gears and bearings are exposed to extreme conditions - friction, contamination, corrosion and poor lubrication can damage them. Over the course of time, damage can occur and spread, and in the worst case, the machines fail altogether. The project, funded by the state of Baden-Württemberg, investigated ways in which simple chemical methods could be used to modify surfaces in such a way as to reduce damage and breakdowns. In certain applications, the new surfaces reduce the failure rate of the components and thus extend the service life of the machines. The processes are now going into broad application.
The aim of the completed project was to achieve a reduction of friction and wear of drive elements through the simplified generation of nanoscale and functionalized nanoscale boundary layers. This objective was associated on the one hand with a reliable function and on the other hand with an increase in service life. Nanoscale metallic materials exhibit technically outstanding properties such as corrosion and wear protection. Established processes are based on demanding process sequences (e.g. mechanical deformation, laser peening), which limit the broad availability. The project was intended to show ways in which nanoscale boundary layers on materials can be produced by simple chemical immersion processes. The wide range of variations suggested that boundary layers with novel properties could be obtained in a targeted manner using simple processes. Practical relevance was achieved by investigating the influence of the modifications on current problems such as false brinelling and fretting corrosion. The modification of the material surfaces leads to changes in the surface topography, the chemical composition of the near-surface area and the microstructure in the near-surface area. Various modifications can be characterized and classified with regard to these three parameters by means of interface analysis. The chemical change/element composition is most obvious. The surface properties such as roughness and contact area are also more or less clearly changed compared to the starting material. The changes mentioned due to the modifications as well as the functionalisations influence the behaviour of the materials modified in this way in tribological tests and in test bench trials. In this respect, they have effects on the tribological behaviour with regard to friction and wear as well as the formation of friction rust. Modifications or functionalizations of material surfaces are increasingly regarded as aids with which properties can be specifically produced that are required for certain applications. For example, fretting corrosion problems in sliding friction applications or fretting corrosion occurring during longer transport distances can be reduced. By shot peening and subsequent modification, the advantages of both methods can be combined, e.g. hardening of the base material and reduction of the broad-running behaviour of oils - e.g. targeted local lubrication. An improved wear behavior through modification and functionalization can lead to prolonged lubricant use and possibly to lifetime lubrication for tribological partners. The mode of action of additives on surfaces can be determined with the aid of the analytical methods applied. This can provide lubricant manufacturers with valuable information on the effective formulation of lubricants.
- Dr. Tilwich GmbH Werner Stehr, Horb
- Fuchs Europe GmbH, Mannheim
- Getrag GmbH & Cie.KG, Untergruppenbach
- Institut für Organische Chemie, Universität Tübingen
- Kompetenzzentrum Tribologie, Hochschule Mannheim
- OSK Kiefer GmbH, Ettlingen
- Robert Bosch GmbH, Stuttgart / Gerlingen
- Voith Turbo GmbH & Co.KG, Heidenheim