| 摘要 |
The subject invention relates to a process for applying a copper layer to a steel filament which comprises: (a) applying a negative charge to the steel filament and continuously passing the steel filament through a plating cell wherein the negatively charged steel filament is in contact with an aqueous copper pyrophosphate solution and wherein the aqueous copper pyrophosphate solution is in contact with a positively charged inert anode; (b) providing the negatively charged steel filament with sufficient residence time in the pyrophosphate solution to plate the steel filament with the copper layer of the desired thickness; (c) replenishing the concentration of copper in the copper pyrophosphate solution in the plating cell by circulating the copper pyrophosphate solution in the plating cell with copper ion replenished copper pyrophosphate solution from a replenishment cell, wherein the replenished copper pyrophosphate solution in the replenishment cell is in contact with at least one copper anode having a positive charge, wherein the replenished copper pyrophosphate solution is in contact with a conductive membrane of a copolymer of tetrafluoroethylene and perfluoro-3,5-dioxa-4-methyl-7-octenesulfonic acid which separates the replenished copper pyrophosphate solution from a potassium hydroxide solution, wherein the potassium hydroxide solution is in contact with a negatively charged cathode; (d) transferring a sufficient amount of the potassium hydroxide solution which is in contact with the negatively charged cathode which produces hydroxide ions to the copper pyrophosphate solution to replenish the hydroxide ions in the copper pyrophosphate solution which are consumed at the inert anode in the copper pyrophosphate solution in the plating cell; and (e) adding a sufficient amount of water to the potassium hydroxide solution to replace the potassium hydroxide transferred to the copper pyrophosphate solution and water lost through reduction and evaporation. <IMAGE> |
