Options
2020
Conference Paper
Titel
Macroscopic friction value control by electrochemical potentials with ionic liquids
Abstract
Electrochemical potentials influence tribological interactions. By using surface-active ionic liquids (ILs), the friction and wear properties on the macroscale can be controlled via electrical potentials. In nanotribological investigations, a reversible switchability of the friction coefficient has already been proven.[1] The mechanisms identified were the change in the surface energy of the substrate, the adsorption of molecules and the resulting structure formation on the surface.[2] In contrast to the nanoscale, these mechanisms are practically unexplored in macroscopic friction contacts. In previous work at the MicroTribologie Centrum (µTC), friction and wear were specifically altered by externally[3,4] and galvanically[5] induced potentials in aqueous mixtures with 1% IL. The macroscopic friction behaviour of different ILs on 100Cr6 steel was investigated in a rotating ball-to-3-pin experiment at electrochemical potentials. At anodic potential, the coefficient of friction increases by up to 45 %. In contrast, cathodic polarization reduces the coefficient of friction by about 10 % compared to the unpolarized state. Due to the structure-dependent interaction of the molecules on the substrate, a strong structure-property relationship could be demonstrated. ILs also react reversibly with the steel at certain electrical potentials, whereby the tribological interactions and thus the coefficient of friction are repeatedly adjusted. In this work it was shown that the friction on the macroscale can also be reversibly changed by electrochemical potentials in a certain range. B y combining friction coefficient measurement and potential control, a system can be developed that automatically adapts to external influences and keeps a given friction coefficient stable or reversibly changes it. Electrochemical potentials influence tribological interactions. By using surface-active ionic liquids (ILs), the friction and wear properties on the macroscale can be controlled via electrical potentials. In nanotribological investigations, a reversible switchability of the friction coefficient has already been proven.[1] The mechanisms identified were the change in the surface energy of the substrate, the adsorption of molecules and the resulting structure formation on the surface.[2] In contrast to the nanoscale, these mechanisms are practically unexplored in macroscopic frict ion contacts. In previous work at the MicroTribologie Centrum (µTC), friction and wear were specifically altered by externally[3,4] and galvanically[5] induced potentials in aqueous mixtures with 1% IL. The macroscopic friction behaviour of different ILs on 100Cr6 steel was investigated in a rotating ball-to-3-pin experiment at electrochemical potentials. At anodic potential, the coefficient of friction increases by up to 45 %. In contrast, cathodic polarization reduces the coefficient of friction by about 10 % compared to the unpolarized state. Due to the structure-dependent interaction of the molecules on the substrate, a strong structure-property relationship could be demonstrated. ILs also react reversibly with the steel at certain electrical potentials, whereby the tribological inter actions and thus the coefficient of friction are repeatedly adjusted. In this work it was shown that the friction on the macroscale can also be reversibly changed by electrochemical potentials in a certain range. By combining friction coefficient measurement and potential control, a system can be developed that automatically adapts to external influences and keeps a given friction coefficient stable or reversibly changes it.
Author(s)
Konferenz