Surface Metallization Of Carbon Fiber And Its Application In Copper Matrix Composites

Copper metal has excellent electrical conductivity,thermal conductivity,ductility and corrosion resistance,and is widely used in electric power,electronics,energy petrochemicals,mechanical metallurgy and other fields.With the increasing demand for copper materials,the low hardness and yield strength of copper and its poor creep resistance have restricted the development of copper materials.At present,copper matrix composites have become a hot spot for research on copper materials because they can take the advantages of both copper matrix materials and reinforcement materials.Carbon fiber(CF)is an ideal reinforcement material for copper matrix composites because of its high specific strength and modulus,high temperature resistance,and fatigue resistance.In this paper,the surface metallization process of short-cut carbon fibers and continuous carbon fibers and their applications in copper matrix composites are discussed respectively,mainly using carbon fibers as the reinforcing phase,as follows:(1)According to the principle of chemical nickel plating,an alkaline chemical nickel plating solution with nickel sulfate as the main salt and sodium hypophosphite as the reducing agent was used for the surface chemical nickel plating of short-cut carbon fibers.The results showed that the metal of the chemically plated nickel layer with sodium hypophosphite as the reducing agent was Ni-P alloy,and the optimum application temperature of the chemical nickel plating was 75℃.The short-cut CF/Cu composites were prepared by mechanical molding method,and the study showed that when the sintering temperature of short-cut CF/Cu composites exceeded850℃,the carbon fibers would react with hydrogen to produce pores,which reduced the performance of the composites,so the optimal sintering temperature was around850℃.The Vickers hardness of the short-cut CF/Cu composites increased with the increase of the volume fraction of short-cut CF.And when the CF content is 30 vol.%,the Vickers hardness of the short-cut CF/Cu composite is 55 HV.(2)According to the principle of electroless nickel plating,an acidic plating liquid system with high-purity nickel plate as the anode,continuous carbon fiber as the cathode and nickel sulfate as the main salt was used to investigate the effects of cathode current density magnitude,nickel plating time and other parameters on the performance of carbon fiber when electroless nickel plating was applied to carbon fiber.The study shows that the electroplated nickel layer is most uniform and dense when the current density is 1.52 A/dm~2.Taking into account the cladding and processability of the electroplated nickel layer,the electroplated nickel carbon fiber with a current density of 1.52 A/dm~2 and plating time of 20 min has the best overall performance,and is selected as the reinforcing phase of CF/Cu composite.The continuous CF/Cu composites were prepared by induction melting method and cold isostatic sintering method,and the comparative analysis showed that the continuous CF/Cu composites prepared by cold isostatic sintering method had excellent wettability.