Investigation On Surface Treatment And Copper Plating Of Carbon Composite Materials

Carbon and its composites have gradually replaced metal materials in more and more fields due to their light weight,high temperature resistance,corrosion resistance,and excellent thermodynamic properties.However,its shortcomings such as wear resistance,conductivity and electromagn etic shielding limit application to some extent.Surface metallization can greatly improve these properties.The chromium used in the traditional roughening is extremely harmful to the environment,and the palladium used in the activation process is costly and resource constrained.In this paper,the metallization of CF/EP(Carbon Fiber Reinforced Epoxy Resin Composites)and carbon rods is realized by chromium-free roughening and palladium-free activation.Screen the coarsening system suitable for CF/EP,an d study the coarsening mechanism,select the silver ion activation method for activation,and further optimize the coarsening and activation system by studying the effect of coarsening and activation on the properties of substrate and coating.Screen and optimize the sealing and electroplating process suitable for carbon rods.The hydrogen peroxide-sulfuric acid-water(H₂O₂-H₂SO₄)coarsening system for CF/EP was screened out by gravimetric method,and the system was evaluated and optimized by orthogonal exp eriment.The best optimized process is to treat the sample in a roughing solution with a volume ratio of 2.5:6.5:1 of hydrogen peroxide,sulfuric acid and water at 35°C for 10 min..The metallurgical microscope and SEM(scanning electron microscope,field emission electron microscope)are used to study the surface state of CF/EP under different roughening conditions.Using FT-IR(Fourier Transform Infrared Spectra)and EDS(Energy Dispersive Spectroscopy)characterize the changes in the bonding state and el ement content of the sample surface.The results show that the carbon-oxygen content ratio decreases after the sample roughened,which proves that the oxygen content increases and the sample surface produces more hydroxyl groups.Hydrophilic oxygen-containing groups such as carboxyl groups.After roughening,CF/EP is activated by nickel ion,silver ion,chemical grafting-silver ion method respectively.The best activation method is chemical grafting-silver activation method.Optimized activation conditions are chemical grafting(1 wt.%3-mercaptopropyltriethoxysilane,20 vol.%ethanol,80 vol.%water,35°C,5 h)and silver ion activation(3.5 g×dm^-3 silver nitrate,Appropriate amount of ammonia,5 min at room temperature),reduction(20 g×dm^-3 sodium borohydride,20g×dm^-3 sodium hydroxide,120 s at room temperature),ultrasonic assisted water cleaning for 10 s.The results show that under the optimal experimental conditions,the silver particles are uniformly covered,and there is no obvious self-decomposition during subsequent electroless plating.The coating was uniform and compact,and the binding force with the substrate reaches the standard.By comparing the plating speed,drying weight loss,and the p H of the carbon rod immersed in the aqueous solution after copper stripping,the carbon rod anti-seepage plating method are screened,and the mechanism of the anti-seepage plating is discussed.Optimize electroplating process according to plating speed and coating morphology.The best sealing process is gaso line immersion for 2?3 min,boiling water short immersion,and natural drying;The composition of the electroplating solution for the best electroplating process consists of 30cm³×dm^-3sulfuric acid?100 g×dm^-3Copper sulfate?2.5 cm³×dm^-3acetic acid and 10cm³×dm^-3addition agent.The best cathode current density is 6 A×m^-2,and the optimal electroplating time is 50 min.After copper protection,the surface state can be maintained for 72 hours in neutral salt spray.