Tribological property of AgNi-CNTs composites under electric current

Abstract

Sliding electrical contacts play a crucial role in many electrical and mechanical devices, allowing for a stable electrical connection between two relatively moving surfaces. The design and material selection for sliding electrical contacts are vital for ensuring the reliability and performance of the equipment. The AgNi-CNTs composites are prepared by powder metallurgy and hot extrusion. The influences of CNTs content and electric currents on their tribological properties are investigated. The results show that the hardness of the composites increases with the addition of CNTs, which is attributed to the dispersion strengthening by the CNTs and the grain refinement strengthening by the smaller Ni particles. The friction coefficient and wear rate of the AgNi-CNTs composites significantly decrease with an increase in the CNTs content, indicating that CNTs can effectively serve as a lubricant and improve wear resistance. The wear rate of the composites is much higher at 1 A than at 0.1 A, which is due to the arcs generated when current flows through the contact interface, showing a combination of electrical and mechanical wear. The lubricating effect of CNTs facilitates the formation of a uniform transfer layer on the CuBe sheet. High current promotes the formation of a thicker transfer layer, which is due to the softening of the AgNi-CNTs composites caused by Joule heating.