Influence of the electrical current on the graphite surface in an electrical sliding contact

• Published in: Surface & coatings technology Vol. 76; pp. 421 - 424
• Main Authors: Csapo, E., Zaidi, H., Paulmier, D., Kadiri, E.K., Bouchoucha, A., Robert, F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.1995
• Subjects: Electrical current; Environment; Friction; Graphite; Environment; Friction; Electrical current; Graphite
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/0257-8972(95)02626-6

The tribological behaviour of graphite-graphite contact is affected by the electrical current. The friction coefficient and wear rate decrease when the contact is crossed by an electrical current, which acts to increase the number of contact asperities and to decrease their sizes. In a previous paper we have shown that, when an electric current crosses a sliding graphite-graphite contact, the friction coefficient decreases (H. Zaidi, E. Csapo, H. Nery and D. Paulmier, Surf. Coat. Technol., 62 (1993) 388–392). Atomic force microscopy and scanning tunnelling microscopy show that the basal planes of surfaces crossed by an electrical current are deformed and contribute to increasing the number of junctions, which enhances the electrical conduction and then influences the tribological behaviour of the graphite in the contact. From the multiplicity and the diversification of our experimental results we have elucidated the principal causes responsible for this phenomenon. It appears that the electrical current has a tendency to modify the orientation of the high density superficial graphitic planes to ease its passage across the oriented graphite layers. In this paper we present and discuss the results obtained with the surface analysis.