**1. Introduction**

This study clearly showed the influence of the degradation of the material on the tribological behavior. However, the diversity of the elements in the presence complicates the interpretation of results.

Finally, the important role of the oxidation has also been highlighted in this study, by its contribution to the degradation of the material on the one hand, to the training of oxides present in the third body, on the other hand. This influence of oxidation could be investigated through the realization of tribological tests under a controlled atmosphere. As an exploratory measure, development on the triometer of an experimental device designed to deprive the contact of the oxygen in the ambient air has been undertaken in this spirit.
