Surface Failure and Repair Technology of Current-Carrying Sliding Friction Components

With the increasing applications of electric energy and development of communication technology, the transmission and conversion of electric energy and electrical single between different parts plays important roles for the operation of equipment. For example, the pantograph and overhead contact wire system takes on the task of providing electricity for high-speed rail, the brushes supply electric powder for the electric motors for new energy vehicles, the electromagnetic rails provide high density current for generating huge Lorentz force of ejection weapon, the conducting joint of radar ensuring the reliable transmission of electrical signals, and so on. These parts always require materials to have high strength, high electrical conductivity, and good wear resistance, but it is very difficult to satisfy all these different requirements synchronously, and hence bring extensive economic cost to produce these key parts. The damage of these parts is mainly caused by the friction and wear with current, which always occurs at the surface of parts, but be treated by replacing with new ones. Such a simple treating method results in enormous economic loss and wasting of resources, and hence surface repairing and remanufacturing has been considered as a potential most promising way to deal with these failure parts. Up to now, there are intensive studies on the surface damage mechanism and prediction of lifetime on the electrical contacting parts, by means of experimental investigation and computer simulation. There are also many more than 15 kinds of repairing techniques and hundreds of material systems had been explored to deal with the surface repairing of the damaged contacting parts.

In this paper, the basic concept of electrical contacting was introduced, and then the surface failure modes of sliding friction parts were summarized in detail, including the common styles mainly resulted from traditional mechanical friction and wear without current along with the special ones with current. Subsequently, experimental investigating methods and computer simulation methods for studying the surface damage mechanism were introduced, where the recent studying results on the failure mechanism and the influencing factors were also incorporated. Finally, the recent progress on the surface repairing techniques and repairing materials that mainly used were summarized, where the advantage, disadvantages, the suitable material systems, as well as the potential resulted performance had also been detailly compared among them. Based on reviewing the current research progress and increasing demands on sliding contracting parts towards high moving speed and large electrical current density, the major existing problems in the research field of sliding electrical contact parts were summarized, and some research ideas on understanding the mechanism of conductive wear resistance and exploring self-lubrication coatings along with optimizing their quality was put forward by combining experimental studying and analogue simulation.