Patent ID: 7422677

Claim:
A method of membrane-mediated electropolishing of a work piece having a surface comprising a metal, the method comprising: A) providing the work piece surface at least partially covered with a low-conductivity fluid, wherein the metal is in electrical contact with a positive terminal of an electrical power source having positive and negative terminals; B) substantially and movably contacting at least a portion of the metal on the work piece surface covered with the low-conductivity-fluid with at least a portion of the first side of an ion-conducting membrane having first and second sides, wherein the second side of that portion of the ion-conducting membrane contacts a conductive electrolyte composition having a conductivity greater than 5 mS/cm, and the ion-conducting membrane substantially prevents the conductive electrolyte composition from contacting the work piece surface; and C) electrically contacting the conductive electrolyte composition with a cathode that is electrically connected to the negative terminal of the electrical power source, thereby applying a voltage, causing an electric current to flow between the work piece and the cathode, and electropolishing metal-containing ions from the work piece surface, and wherein a majority of metal-containing ions electropolished from the work piece migrate through the ion-conducting membrane and into the conductive electrolyte composition.