Research On Surface Metallization Modification Of Carbon Fiber

Due to the excellent mechanical and physical properties of carbon fiber,carbon fiber reinforced metal matrix composites have wide application prospects in various fields.But,it is difficult to give full play to the mechanical properties of carbon fiber due to its high inertness,large contact Angle with metal matrix,poor wettability and other interface compounding problems.At present,surface metallization is an effective method to solve the interface problem between carbon fiber and metal.In order to increase the wettability of carbon fiber and metal,this experiment firstly oxidized carbon fiber with nitric acid,and then metallized carbon fiber.The effects of different electroplating parameters on the coating were studied.SEM and XRD were used to characterize the coating.Nitric acid oxidation on the surface of carbon fiber showed that: after ultrasonic treatment with concentrated nitric acid,the axial furrows on the surface of carbon fiber would become deeper,the fine grooves would be oxidized away,the roughness increased,and the fringe increased slightly.After nitric acid oxidation,many hydrophilic functional groups,such as C-O-,C=O,COO,etc.are formed on the surface of carbon fiber,which can effectively increase the wetting property of carbon fiber and electroplating solution.In this paper,Ni,Cu and Ni/Cu coatings were deposited on the surface of carbon fiber by electrochemical deposition method.The modified composite wire was used to explore the influence of coating on the mechanical properties of carbon fiber and the influence of electroplating on continuous fiber resistivity.The optimal electroplating process was determined by controlled experiments: Ni plating temperature was 25℃,p H was 5,electroplating time was 6min,current density was 0.5 A/dm2,and voltage intensity was 10 V.Cu plating temperature was 45℃,p H was 8,electroplating time was 6min,current density was 0.7A/dm2,and voltage strength was 10 V.After electroplating continuous carbon fiber,Ni-coated composite wire,Cu-coated composite wire and Ni /Cu double-coated composite wire can be obtained.The test results showed that the Ni coating and Ni /Cu double coating were uniform and flat,with solid interface connection,high purity and strong adhesion.Cu coating surface has fallen off,most can be electroplated complete,but there is still a black heart,so the first nickel plating is better than the first copper plating.After electroplating,the strength of single filament is slightly improved or basically unchanged,while the modulus of single filament decreases by about 10%,and the mechanical properties of carbon fiber can be maintained.After electroplating,carbon fiber resistivity decreases by two orders of magnitude and conductivity increases sharply.