Method and apparatus for continuously applying nanolaminate metal coatings
Described herein are apparatus and methods for the continuous application of nanolaminated materials by electrodeposition.
1. An apparatus for electrodepositing a nanolaminate coating, comprising:
an electrodeposition cell for use with a conductive workpiece, the electrodeposition cell being configured for movement of the conductive workpiece therethrough at a rate;
an electrolyte in the electrodeposition cell, the electrolyte comprising salts of two or more electrodepositable metals;
a rate control mechanism operable to control the rate at which the conductive workpiece moves through the electrodeposition cell;
an electrode; and
a power supply configured to control a current density applied to the conductive workpiece in a time varying manner as it moves through the electrodeposition cell, wherein controlling the current density in a time varying manner comprises repeatedly applying three or more different current densities to the conductive workpiece as it moves through the electrodeposition cell, the power supply further configured to apply an offset current to the conductive workpiece so that the conductive workpiece remains cathodic when it is moved through the electrodeposition cell and the electrode remains anodic.
2. The apparatus of claim 1 , wherein the time varying manner comprises one or more of: varying a offset current, a pulse current modulation and a reverse pulse current modulation.
3. The apparatus of claim 1 , wherein the electrodeposition cell further comprises an ultrasonic agitator.
4. The apparatus of claim 3 , wherein the ultrasonic agitator operates continuously or in a pulsed fashion.
5. The apparatus of claim 1 , further comprising a first location, from which the conductive workpiece is moved to the electrodeposition cell, and/or a second location, for receiving the conductive workpiece after it has moved through the electrodeposition cell.
6. The apparatus of claim 5 , wherein the first location, the second location, or both comprises a spool or a spindle.
7. The apparatus of claim 6 , wherein the conductive workpiece is a wire, rod, sheet or tube that can be wound on the spool or around the spindle.
8. The apparatus of claim 1 , wherein the electrolyte is an aqueous electrolyte.
9. The apparatus of claim 1 , wherein the electrolyte is a non-aqueous electrolyte.
10. The apparatus of claim 1 , wherein said electrolyte comprises salts of three or more electrodepositable metals.
11. The apparatus of claim 5 , further comprising one or more locations between the first location and the electrodeposition cell, where the conductive workpiece is contacted with one or more of: a solvent, an acid, a base, an etchant, and a rinsing agent to remove said solvent, acid, base, or etchant.
12. The apparatus of claim 5 , further comprising one or more locations between the electrodeposition cell and the second location, where the conductive workpiece is subject to one or more of: cleaning with solvent, cleaning with acid, cleaning with base, passivation treatments, and rinsing.
13. The apparatus of claim 1 , further comprising a mixer for agitating the electrolyte.
14. The apparatus of claim 13 , wherein the mixer variably mixes the electrolyte placed in the electrodeposition cell.
15. The apparatus of claim 1 , further comprising a flow control unit for applying the electrolyte to the conductive workpiece.
16. The apparatus of claim 1 , further comprising a plurality of rotating elements in the electrodeposition cell, the plurality of rotating elements being arranged such that the conductive workpiece travels in a serpentine path guided by the plurality of rotating elements.