Study Of The Metal Cladding Onto Carbon Fibers And The Characteristics Of Interface Bonding Of Metal-coated Carbon Fibers

Carbon fiber is a very ideal reinforcement to make the copper based composite on account of its excellent performance such as high specific strength and modulus, thermostability, fatigue resistance, low inflation and self-lubricating etc. But it is well known that the wettability between it and copper is poor. So it is often required to carbon fiber’s surface treatment.Three kinds of metal-coated carbon fibers(copper-coated, nickel-coated and double copper/nickel-coated) were prepared based on electroless plating process. pH of solution, reaction temperature and deposition time on deposition rate and the surface morphology of the coating in carbon fibers have been discussed. The optimal technology of electroless plating Ni on Cf were pH value 8.0, temperature 75℃, plating 3 min. The optimal technology of electroless plating Cu on Cf were NaOH 14g/L, temperature 35℃, plating 5min. When carbon fiber electroless Cu/Ni plating, after plating Cu, plating Ni induced reaction is required.Three kinds of metal-coated carbon fibers heat treatment at a temperature of 750℃. The surface appearance, chemical composition, phase constitution and the microstructure of carbon fiber of metal-coatings were investigated with scanning electron microscope(SEM), energy dispersive spectrometer(EDS) and X-ray diffraction(XRD) respectively. The results show that, before and after heat treatment, the interface bonding of copper-coated carbon fiber is always mechanical bonding, and mechanical bonding is turned into diffusion bonding for nickel-coated and double copper/nickel-coated carbon fibers. The heat treatment hardly affects the microstructure of carbon fiber with copper coating, and induces the graphitization for nickel and double copper/nickel-coated carbon fibers. However, it indicates that copper layer can effectively not only decrease the degree of graphitization induced by nickel but also guarantee diffusion bonding of interface.Using vacuum hot-pressing sintering CF/Cu composites, carbon fiber volume content is 5%, 15% and 25%. Then the density, HV value and electrical conductivity of CF/Cu composites is analyzed. Results were as follows: With the increase of fiber volume percentage, real density and electrical conductivity decreasing, hardness increasing. As the interface bonding characteristics were difference, the property of CF/Cu composites were difference, specific as follows: Cu/Ni double coating carbon fiber reinforced copper matrix composites have a higher density than the Cu plating carbon fiber reinforced copper matrix composites, but lower than the Ni plating carbon fiber reinforced copper matrix composites. Hardness is higher than the Cu plating carbon fiber reinforced copper matrix composites, more higher than the Ni plating carbon fiber reinforced copper matrix composites; Electrical conductivity is lower than the Cu plating carbon fiber reinforced copper matrix composites, but significantly higher than the Ni plating carbon fiber reinforced copper matrix composites.