Baths Used in Copper Electroplating Process

Baths Used in Copper Electroplating Process

Copper cyanide plating is widely used in many plating operations as a strike. However, its use for thick deposits is decreasing. For copper cyanide plating, cuprous cyanide must be complexed with either potassium or sodium to form soluble copper compounds in aqueous solutions. Copper cyanide plating baths typically contain copper cyanide and either potassium cyanide or sodium cyanide. Current densities range from 54 to 430 A/m2. Cathode efficiencies range from 30 to 60 percent.

Baths used in copper plating include copper pyrophosphate and copper sulfate baths. Copper pyrophosphate plating, which is used for plating on plastics and printed circuits, requires more control and maintenance of the plating baths than copper cyanide plating does. However, copper pyrophosphate solutions are relatively nontoxic. Copper pyrophosphate plating baths typically contain copper pyrophosphate and potassium pyrophosphate. Current densities range from 110 to 860 A/m2.

Copper sulfate baths, which are more economical to prepare and operate than copper pyrophosphate baths, are used for plating printed circuits, electronics, rotogravure, and plastics, and for electroforming and decorative uses. In this type of bath copper and sulfate and sulfuric acid form the ionized species in solution. Copper sulphate plating baths typically contain copper sulphate and sulfuric acid. Current densities range from 215 to 1,080 A/m2.