Study On Plating Au-Cu Alloy In Non- Cyanide Sulfite Pulse Plating Process

Because of the excellent chemical stability, electrical conductivity and high-temperature resistance, Au and its alloy coatings are often used to improve the components’surface performances. Au and its alloy coatings are also used in electronic industries, they apply to make the components which need the long-term stability of electric parameters. In traditional cyanide plating process, the plating solutions have good throwing power, covering ability and stability of the bath were good, and the properties of the coating are good too. However, this process need to use cyanide, the cyanide is poisonous, bad for the workers’health and environment. Then, the non-cyanide plating process becomes the main research direction of electroplating workers.Comparing the sodium sulfite-ammonium citrate Au-Cu alloy plating process and the sodium sulfite-complex a Au-Cu alloy plating process, considering the performance of the coating and plating solution, I decide the sodium sulfite-complex a Au-Cu alloy plating process to be the object of my study. Choose the Coating appearance, coating hardness and plating solution deposition rate to be the evaluation indexes, gain the optimization formula of the sodium sulfite-complex a Au-Cu alloy plating process:Au lOg/L, CuSO4 1g/L, Na2SO5 170g/L, K2SO480g/L, complex a 60g/L. Meanwhile, I study the impact of Different plating process parameters on the coating surface quality and plating solution deposition rate. Then, gain the optimization process parameters:current density Ak= 0.3A/dm2, temperature= 50℃, duty cycle= 10%, frequency=1200Hz, pH=9, the stirring speed=1000r/min.In the sodium sulfite-complex a Au-Cu alloy plating process, the plating solutions have good throwing power, covering ability and stability of the bath were good, the current efficiency is 82.23%. the Au-Cu coating’s binding force and corrosion resistant are good; the hardness is 190.43Hv, bigger than gold’s or copper’s; the XRD test’s result indicates the coting composed by Au3Cu solid solution; the XRF test’s result indicates in the coating gold’s mass fraction is 90.23% and copper’s is 9.77%.