Study On The Process Of Non-cyanide Copper Plating And The Film Properties Based On The Citric Acid System

For its good electrical conductivity, thermal conductivity and ductility, Copper iswidely used in electronic and decorative fields. Using highly toxic cyanide, traditionalcyanide copper plating has great safety hazards and environmental pollution. As theawareness of environmental protection, to prevent cyanide plating has gradually beingput on the agenda. People eager to have non-cyanide copper system to completelyreplace cyanide plating.Based on more groups of citric acid copper plating system, comparative study wasdid and identified citric acid-potassium sodium tartrate complex non-cyanide coppersystem as my research object. Aiming at the problem of adhesive strength was notstrong, the components of additive was optimized by orthogonal test. Then put forwardand carried out the preparation of non-cyanide copper plating under the normaltemperature.By single factor experiment examines, complex-ratio, Cu2+concentration, additivesand process conditions were investigated on the coating appearance condition,microstructure of cathodic polarization, current efficiency and plating solution. Thenused orthogonal test to further optimize the composition of plating solution and processconditions, and obtained the system optimal formula.Under this condition, the platingsolution has good plating and deep plating ability and stability, and the microstructure ofthe coating, bonding strength is also well. The process proved that the technology hasthe possibility of production application and prospects.The copper layer under the optimal process was characterized by SEM, XRD andother means. The results showed that the coating grain is fine smooth, uniform, lowporosity, preferred orientation. By the adhesive peel test verified the copper layer andthe substrate has good bonding strength too.Cyclic voltammetry and other electrochemical methods were used to inquiry citricacid copper plating system of the mechanism of the copper deposition process andadditives. The results showed that citric acid copper plating system possesses isstable and successful nuclear ring exists in the process of electrode position and copperdeposition process is irreversible.By the kinetics of electrochemical test, in the process of deposition potentialdecrease, plating activation energy is less. Additive increases the solution of the cathodepolarization effect, making the coating evenly.