Wear mode of a copper wire during a sliding contact with copper/chrome steel: influence of oxygen
Abstract
The wear of the overhead lines that bring current to railway electrical engines necessitates an expensive renewal. The nature of the collector rod plays an important part on the wear. We have studied here the mechanisms of wear under various environments without current. It appears that active gases (dry air, humid air, water vapour, oxygen) have low influences on the friction coefficient. The contact occurs through an oxide layer which is harder than the metal and protects it from plastic deformations. In the presence of pure argon, the wear rate is low, in the presence of air, it is multiplied by a factor of three and with pure oxygen by a factor of six. This study shows that the wear of the copper wire essentially comes from oxidation. The growth of the oxide layer increases its brittleness. Under the sliding stresses by the collector rod, the oxide layer breaks and small particles including metal break off and roll in the contact interface. The abrasive effect of the chrome oxide coming from the collector rod strongly increases the wear of the copper wire.
- Publication:
-
Vacuum
- Pub Date:
- January 1990
- DOI:
- 10.1016/0042-207X(90)94232-F
- Bibcode:
- 1990Vacuu..41.2230P