This invention provides membrane-mediated electropolishing (MMEP)
processes for polishing and/or planarizing metal work pieces using
topographically patterned membranes. The processes can be used for both
pure metals and alloys, and provide advantages over conventional
electropolishing processes and known MMEP processes using smooth
membranes. This invention also provides a cathode half-cell and an
apparatus useful in membrane-mediated electropolishing processes. The
invention also provides processes for electroengraving and
electromachining topographic patterns, holes and/or grooves into the
surface of a metal work piece.