Study on Electroconductive Tribological Properties of Ag-Based Composite Coating

Electrical contacts are widely utilized in numerous engineering applications that require high reliability. However, fretting wear due to repeated contact may lead to increased electrical contact resistance that can cause failure of the electrical system. Herein, an Ag-based coating was prepared by an electroless co-deposition technique in order to improve the electroconductive properties under fretting conditions. By carefully controlling the deposition time, a relatively smooth and continuous Ag coating could be obtained. The structure of the coating was analyzed using X-ray diffraction, 3D confocal microscopy, and scanning electron microscopy techniques. The electroconductive tribological properties of the coating were assessed using a custom-built fretting tester. The Ag coating possessed good crystallinity and exhibited improved electroconductive properties compared with the Ni interlayer deposited on a steel substrate. The high temperature of the contact zone generated by friction contributed to the reduced electric resistance. Furthermore, incorporation of graphene as a dopant could improve the coating wear resistance, resulting in more reliable electroconductive properties in the fretting condition. The wear mechanism of the coating was also investigated through wear track analysis. The experimental results are expected to aid in understanding the electroconductive tribological properties of Ag coatings used in electrical contact applications.