GB822895A - Reducing electrically conducting metal oxide films - Google Patents

Abstract

822,895. Electrolysis. LIBBEY-OWENSFORD GLASS CO. Nov. 12, 1955, No. 32412/55. Class 41. A method of reducing an electrically conducting metal oxide film, e.g. transparent tin oxide, on a non-conducting surface, e.g. glass, to its metal, comprises passing a direct current through at least a portion of the film and through an acidic liquid electrolyte, e.g. a 50% hydrochloric acid solution, which is rubbed in contact with the film. The hydrochloric acid subsequently dissolves the tin. An apparatus for carrying out the method comprises an insulating base 11 having a handle and conducting, e.g., copper, plates 13 each covered with an absorbent pad 16, e.g. of felt, alternate plates 13 being connected respectively to the positive and negative poles of a direct current source through terminals 14 and wires 15. In use, the apparatus is dipped in the electrolyte, which, being an acid, removes the metal after reduction of the oxide, and the apparatus, connected to the current source, is rubbed over the film. Reduction is due to the production of atomic hydrogen. Where the film to be removed is a tin oxide strip along an edge of a glass sheet, the strip may be made cathodic and the apparatus then comprises a single copper strip covered with felt and mounted on an insulating base. The copper is made anodic. Tin oxide films on two opposite edges of the glass may be removed by applying temporary silver electrodes on the two remaining edges to make all edges cathodic during cleaning. Specifications 803,371 and 809,936 are referred to.