Comparison of Microstructures and Wear Properties of Silver Coatings for Electrical Contact Prepared by Air Supersonic Flame Spraying, Cold Spraying and Electroplating

Abstract

The electrical contact is a pivotal component in the power transmission system, whose failure mode is closely related to the wear property of the coating on it.In this work, the silver coating was prepared by air supersonic flame spraying and cold spraying(CS).Subsequently, the reciprocating friction test was used to study the friction and wear properties of the coatings under different loads and frequencies, and the results were compared with the property of coatings fabricated by using electroplating.The scanning electron microscope(SEM)and X-ray energy spectrometer(EDS)were used to investigate the morphology and composition of the worn surface, and the friction and wear mechanisms of the coatings were analyzed and discussed.Results showed that both air supersonic flame spraying and CS processes could prepare thicker and denser silver coatings.The silver coatings prepared by cold spraying presented higher microhardness, smaller friction coefficient and lower wear loss under the high frequency and high load conditions.Besides, the wear mechanism of silver coating prepared by air supersonic flame spraying and CS was mainly fatigue wear.

Keywords

• electrical contact|silver coating|air supersonic flame spraying|cold spray|electroplating; friction and wear