Process for electroplating metals
AssigneeEco-Tec Limited
InventorCraig J. Brown
Life of this patent
Estimating the term…
Abstract
A process for electroplating metals in an electroplating cell in which the anode current efficiency of the cell is greater than the cathode current efficiency. Buildup of excess metal in the cell is counteracted by circulating the plating solution through an electrowinning cell and plating out the excess metal onto cathodes in the electrowinning cell. The amount of current flowing through the electrowinning cell is controlled so that the amount of the said current which results in the deposition of metal is at least substantially equal to the amount of current flowing through the electroplating cell which results in the evolution of hydrogen gas.
Claims15
A process for electroplating metals in an electroplating cell which comprises a bath containing a plating solution of a metallic salt, a cathode comprising a workpiece to be plated, and a soluble anode, and in which the anode current efficiency of the cell is greater than the cathode current efficiency;
- said process comprising the steps of:
- providing an electrowinning cell which includes at least one insoluble anode, at least one insoluble cathode and a bath which communicates with the bath of said electroplating cell for permitting circulation of said plating solution between said cells;
- connecting a source of direct electric current across the anode and cathode of said electroplating cell so as to cause electroplating of metal onto said workpiece;
- circulating said plating solution between said cells;
- connecting a source of direct current across said anode and cathode of the electrowinning cell so as to cause deposition of metal from said plating solution onto said cathode;
- and,
- controlling the amount of current flowing through the electrowinning cell which results in the deposition of metal to be at least substantially equal to the amount of current flowing through the electroplating cell which results in the evolution of hydrogen gas.
An apparatus for electroplating metals comprising:
- an electroplating cell including a bath for containing a plating solution of a metallic salt, a cathode comprising a workpiece to be plated, and a soluble anode, the anode current efficiency of said cell being greater than the cathode current efficiency;
- an electrowinning cell which includes a bath and at least one insoluble anode;
- means for coupling said electroplating cell bath with said electrowinning cell bath for permitting circulation of said plating solution between said cells;
- a source of direct electric current for connection across the anode and cathode of the electroplating cell for electroplating a metal onto said workpiece;
- and,
- a source of direct current for connection across said anode and cathode of the electrowinning cell so as to cause deposition of metal from said plating solution onto said cathode.
Dependencies are inferred from the claim text.