Investigation of electrochemical and electrotribological interactions

Chemical processes take place in all tribological contacts. Since chemical interactions are generally characterized by bonding electrons and electron transitions, it is possible to influence them by means of electrical voltages. Electrochemical methods can be used to investigate and influence chemical reactions in tribological contacts.

 

Benefits of electrochemical methods

Lubricant development, triboelectrochemical wear protection

Electrically conductive lubricants, control of friction, water-based lubrication, plain bearing optimization

Hydrogen embrittlement (rolling bearings, lubricant development)

Optimization of rolling bearings, E-mobility

Publications  

 

Current development topics

  • Lubricant development for rolling bearings
  • Electrically conductive lubricants
  • Ionic liquids as lubricant additive
  • Measurement of breakdown voltage in rolling bearings

 

 

© Fraunhofer IWM

Lubricant development, triboelectrochemical wear protection / Electrically conductive lubricants, control of friction, water-based lubrication, plain bearing optimization

 

Determination of electrochemical parameters (including corrosion potential, corrosion current density, passivation, electrical conductivity, decomposition). Carrying out electrotribological model friction tests with different load collectives (including oscillating ball-disk, rotating ball-3-pins) to determine the influence of electrochemical potentials on friction, static friction, wear and corrosion behavior. The aim of current work is to specifically control friction and wear by means of electrochemical potentials (CPM cluster, programmable friction) and to develop electrically conductive lubricants (e.g. for e-mobility).

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© Fraunhofer IWM

Hydrogen embrittlement (rolling bearings, lubricant development)

 

By using electrochemical methods, the tribologically induced hydrogen permeation will be measured in-situ during a model friction test (oscillating ball-disk) depending on the load spectrum, the lubricant composition (base oil, additives) and the material. Current research work is concerned with the development of new lubricants to reduce hydrogen-induced damage (e.g. white etching cracks, WEC) in rolling bearings (e.g. for wind turbines).

 

© Fraunhofer IWM

 

 

 

 

 

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© Fraunhofer IWM

Optimization of rolling bearings, E-mobility

 

Application-oriented electrotribological tests to investigate the influence of electrochemical potentials on friction and wear are carried out on axial rolling bearings. The breakdown voltage of lubricants is investigated by specifying certain voltage patterns. In current work, this is measured as a function of the chemical composition, viscosity and additivation of the lubricants. Further investigations are concerned with the influence of electrical potentials on friction and wear in electrically conductive lubricants.

 

 

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Publications

 

  • Gatti, F.; Amann, T.; Kailer, A.; Baltes, N.; Rühe; J.; Gumbsch, P., Towards programmable friction: control of lubrication with ionic liquid mixtures by automated electrical regulation, Scientific Reports 10/1 (2020) Art. 17634, 10 Seiten Link
  • Oberle, N.; Amann, T.; Kürten, D.; Raga, R.; Kailer, A., In-situ-determination of tribologically induced hydrogen permeation using electrochemical methods, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234/7 (2020) 1027-1034 Link
  • Gatti, F.; Amann, T.; Kailer, A.; Abicht, J.; Rabenecker, P.; Baltes, N.; Rühe, J., Makroskopische Reibwertsteuerung durch elektrochemische Potentiale mit ionischen Flüssigkeiten, Tribologie und Schmierungstechnik 66/4-5 (2019) 59-65 Link
  • Kürten, D.; Khader, I.; Kailer, A., Wasserstofffreisetzung im Wälzkontakt, Tribologie und Schmierungstechnik 66/4-5 (2019) 44-50 Link 
  • Amann, T., Gatti, F., Oberle, N.; Kailer, A.; Rühe, J., Galvanically induced potentials to enable minimal tribochemical wear of stainless steel lubricated with sodium chloride and ionic liquid aqueous solution, Friction 6/2 (2018) 230-242 Link  
  • Amann, T.; Waidele, M.; Kailer, A., Analysis of mechanical and chemical mechanisms on cavitation erosion-corrosion of steels in salt water using electrochemical methods, Tribology International 124 (2018) 238-246 Link  
  • Amann,T.; Dold, C.; Kailer, A., Potential controlled tribological behavior of water-based ionic liquids, Key Engineering Materials 674 (2016) 250-256 Link  
  • Dold, C.; Amann, T.; Kailer, A., Influence of electric potentials on friction of sliding contacts lubricated by an ionic liquid, Physical Chemistry Chemical Physics PCCP 17/16 (2015) 10339-10342 Link 

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