The Preparation, Friction And Wear Properties Of Electrical Contact Graphene(Graphite)-silver Matrix Composites

Graphene-silver composites, MoS2-silver composites and graphite-silver composites with Sm adding were prepared by powder metallurgy method. Microstructures and surface topographies after friction and wear of composites were analyzed by microscopic analysis. And the effects of graphene, graphite and Sm on the physical and mechanical properties of the composites (static) were analyzed. Friction and wear tests of composites under current were conducted to research friction and wear properties of composites at different current density conditions.Element Sm was added in graphite-silver composites to improve the properties of friction and wear in an energized state or high current condition. With Sm (oxide) addition amount increasing, resistivity, hardness and bending strength of composites increase. So samarium (oxide) amount added at 3wt% or less. In friction and wear experiments, the wear resistance of graphite-silver composites is significantly improved by samarium adding. And the wear volume of composites decreases.Graphite was replaced by graphene. Graphene-silver composites were prepared by powder metallurgy method. When carbon content is 6wt%, the static properties of graphene-silver composites is better than that of graphite-silver composites. With the substituted amount of graphene increasing, static properties of graphene-silver composites decrease. In friction and wear experiment, with the substituted content of graphene increasing (6wt%,8wt%,10wt%), the wear resistance of composites decreases.MoS2 is a commonly used solid lubricant. It has been widely used in the aerospace as a self-lubricating material. Graphite was replaced by MoS2. MoS2-silver composites were prepared. The effects of M0S2 content on the conductivity and strength of composites was researched. And the properties of the composites were compared with the same lubricant percentage of graphite-silver composites.The electrical friction and wear tests were conducted with three composites. At a constant current density condition, the wear resistances of the composites are graphite (6wt%)-silver composite with 2wt% samarium adding, graphene(6wt%)-silver composite, graphite(6wt%)-silver composite. With the current density increasing, the wear volume of composites increases. The wear volume of positive brush is greater than that of negative brush.The results show that the conductivity, hardness and strength of traditional graphite-silver composites are improved by samarium adding. And the wear properties and electrical contact properties of composites are also improved. Graphite is replaced by graphene. The static properties of graphene-silver composite with low graphene content are better than that of graphite-silver composite. MoS2 is replaced by graphene. The static properties of composites are not obviously improved, and the friction and wear performances of MoS2-silver composites are worse than that of graphite-silver composites under atmospheric condition.