Surface modifications induced by the friction of graphites against steel

The results of the series of tests under “low” loads indicated that the friction coefficient and the transfer film forming tendency increased with increasing load, due to the modification of the morphology of the contact area. Whereas experiments under “high” loads revealed the existence of a critical load at which a sudden decrease of both the coefficient of friction and the transfer film forming tendency is observed. The reorientation of the graphitic planes is supposed to be at the origin of this phenomenon.