COLORED ZINC COMPOSITE PLATED STEEL SHEET AND ITS PRODUCTION

• Main Authors: SHINDO YOSHIO, MURATA TOSHIMICHI, SAITO KATSUSHI
• Format: Patent
• Language: English
• Published: 03.03.1988
• Subjects: APPARATUS THEREFOR; CHEMISTRY; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; METALLURGY; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS

PURPOSE:To obtain a blackened Zn composite plated steel sheet having fine appearance, superior workability and corrosion resistance by electrolyzing a steel sheet as the cathode in an acidic aq. soln. contg. Zn ions, coloring metal ions and highly oxidative ions. CONSTITUTION:A steel sheet, a stainless steel sheet or a steel sheet plated with Zn, Al, Sn or the like is immersed in an acidic plating soln. of 1-4pH contg. 20-100g/l Zn ions and 10-50g/l ions of one or more kinds of coloring metals such as Ni, Co, Fe, Cr, Sn and Cu in 0.1-1.0 ratio of coloring metal ions to Zn ions, and further contg. 1-50g/l highly oxidative ions such as NO3, NO2, ClO4 or ClO3 ions and a specified water soluble high molecular compound as a brightener. Electric current is then supplied at 10-100A/dm current density with the steel sheet as the cathode to form blackened composite plating contg. Zn and the coloring metals as the principal components, and the plated steel sheet is coated with a guard coat of <=3mum thickness such as film formed by chemical conversion treatment.