Influence of the electrical sliding speed on friction and wear processes in an electrical contact copper–stainless steel

Among the various parameters that influence the friction and wear behaviour of a copper–stainless steel couple crossed by an electrical current and in a dry contact is the sliding speed.The testswere carried out underambient environment and the sliding speed was in the range of 0.2–8 ms 1. The electrical current intensity was varied from0 to 40 Aand held constant during each experiment. The normal load was maintained constant corresponding to an average Hertzian stress of 107 Pa. It appears that the friction coefficient and thewear rate increase at first with the speed, reach theirmaximums, then slowly decrease and tend to constant values. Over the entire range of sliding speeds two types of wear are observed. These latters are essentially mild wear as long as hard debris do not appear at the interface and severe wear when debris consisting of oxides or oxide metalmixture become big enough, they are removed from the surface and have abrasive effect. The results are discussed in terms of observations of wear debris size and composition, wear track study, metallographic study of worn surfaces and friction and electrical contact resistance records. # 2003 Elsevier B.V. All rights reserved.