Articles

Tribo-electrochemical behavior of a ferritic stainless steel under applied potentials

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Abstract

A tribo-electrochemical characterization of a ferritic stainless steel has been carried out under reciprocating sliding against a corundum alumina pin in 0.02 M H2SO4 medium at room temperature. Theaim of this study is to present a refinement of the usually employed method to determine the synergismeffect occurring in a tribo system where the sample is made of passive metal and the counter body made ofinert material. The effects of mechanical, corrosion and synergistical contributions to tribocorrosion at eachinvestigated potential are discriminated. So as to further study the synergy, it is divided into two parts,electrochemistry-accelerated wear (EAW) and wear-accelerated electrochemistry (WAE), respectively.
Focus is first addressed on the mechanical wear reference determination under cathodic polarization. It has been shown that depending on the selected cathodic potential a hydrogen effect or even a dissolution
contribution could result in EAW contribution of about 60% of the overall degradation. These effects are avoided when polarization is made at a potential where the double layer thickness is maximum and could
serve as lubricant agent under friction. The wear volume found under these conditions could therefore be used as mechanical wear reference. In the anodic domain, with the employed set-up, it is possible to set an
idle time long enough for the film to reform between each sliding. Charges released during pin motions periods are thus related to depassivation process only and are converted into WAE wear volumes using the Faraday’s law. Wear volumes are quite constant over the investigated range in the passive plateau. They are more important than what is observed at lower potentials because of great EAW wear volumes.
However, the proportions of wear contributions to the overall material degradation are changing. Even if the mechanical contribution is quite constant over the considered passive range around 23%, a transfer is
occurring from the EAW contribution to the WAE one as the anodic potential is increased.

Keywords: ferritic stainless steel, tribocorrosion, mechanical wear reference, synergy

How to Cite:

Dalbert, V., Mary, N., Verdu, C., Evin, H. & Normand, B., (2014) “Tribo-electrochemical behavior of a ferritic stainless steel under applied potentials”, International Journal of Sustainable Construction and Design 4(2). doi: https://doi.org/10.21825/scad.v4i2.1037