The Fabrication And Test Of Silver-copper Coated Graphite Composite

In this paper ,the fundamental principles and basic technicals about copper coat on the surface of graphite powder by electroless plating was discussed .The surface of the graphite powder was autocatalytic so this fine powder less than 38um could be coated with copper successfully without sensitization and activation ;this technical also did for carbon fibre. With this method the copper plating graphite powder was made up in 50% copper content .The silver- copper plating graphite composite was prepared while the silver- copper-graphite composite and the silver-graphite composite were also made up together .The mechanical and electric characteristics of the three kinds of composites were tested and it was found that the copper plating graphite powder can only optimize the properties of the silver matrix composite under the high content of the graphite ,the conductivity and the mechanical property was improved and the material could take higher current in the same carbon content .At 20% carbon content, the resistivity of Ag-graphite composite was 1.67 times as high as that of silver- copper plating graphite composite, the resistivity of Ag-Cu-graphite composite was 3.23 times as high as that of silver- copper plating graphite composite. The bending strength of silver-copper plating graphite composite was 2.17 times as high as that of silver- copper-graphite composite, and the bending strength was 2.11 times as high as that of silver- copper-graphite composite. The wearability of silver- copper plating graphite composite was also enhanced greatly at high carbon content.The metallograph showed that the graphite powder was coated with very fine copper cladding material ,the distribution of the metal was improved with copper plating graphite powder in high carbon content for the nice triaxiality electric conduction net was created in this conditionIt is also found that the silver- copper plating graphite composite could expand obviously in the agglomeration while the globuling of the copper cladding material was very seriously. Those did damage to the composite so future study about the material was necessary.