The Production of Plane Surfaces on Single Crystals of Copper and Copper Alloys

Chemical and electrochemical polishing methods which allow submicroscopically smooth optically flat surfaces to be produced on crystals of copper and copper alloys are described. This is made possible by the use of solutions for cloth chemical polishing which have as additives nitrogen-containing mercapto-sulfur compounds and surface active agents, which facilitate rapid flattening of the surfaces. Conditions for producing surfaces with the best compromise between flatness and submicroscopic smoothness have been worked out. A new system in which an endless cotton belt, saturated with a phosphoric acid electrolyte containing chromic acid, moves between a stationary cathode and the stationary anodic specimen has been introduced for electrochemical finishing. This almost eliminates the fine grained structure often seen on electropolished surfaces of alloy crystals.