TRIBOLOGY

Tribology testing with the Alemnis Standard Assembly (ASA) is possible in several different configurations, depending on the application. For example, the scratch testing option can be used to apply a constant or progressive applied load and then perform a tribology test with synchronized measurement of the tangential force. The friction coefficient is then recalculated from the ratio of the tangential force to the applied load. Such linear tribology tests can be performed either as a single pass, or as a multipass test. Another way to perform tribology tests is to use the Ultra High Strain Rate (UHS) option and use the lateral measurement axis of the SmarTipto measure the tangential force during the test. This opens up a whole new range of possibilities as the friction coefficient can then be measured in two perpendicular axes (with UHS-1-3 and UHS-3-3 options) and with a wide range of frequencies.

Examples of high frequency cyclic lateral oscillation tests on copper (left) and silicon (right) with a conical diamond indenter and lateral frequency 500 Hz applied over 2 ms

The example shown gives an idea of typical tribological wear scars seen in the SEM after tests made on copper and silicon with a lateral oscillation frequency of 500 Hz. Such tests are commonly used to evaluate the resistance of materials to fretting failure (fretting wear being defined as the surface damage which occurs between two contacting surfaces experiencing cyclic motion with very small amplitudes).

Selected References

  1. Major, R. Major, M. Kot, J. M. Lackner and B. Major, Ex situ and in situ nanoscale wear mechanisms characterization of Zr/ZrxN tribological coatings, Wear 404-405 (2018) 82-91
  2. Isard, I. Lahouij, P. Montmitonnet and J-M Lanot, Third body formation by selective transfer in a NiCr/AgPd electrical contact. Consequences on wear and remediation by a barrel tumble finishing, Wear 426-427 (2019) 1056-1064