| 摘要 |
1289335 Electro-depositing nickel and/or cobalt; cleaning steels FARBENFABRIKEN BAYER A G and FRIEDR BLASBERG GmbH und Co K G 7 Oct 1969 [10 Oct 1968] 49138/69 Headings C7B and C7E Steel plate is pretreated for enamelling by degreasing, pickling, metallizing and drying, the metallizing comprizing electro-depositing Ni and/or Co on to the surfaces to be enamelled in a quantity of 0À2-0À7 g/sqm from an aqueous acid plating bath containing Mg and Cl ions. The bath may contain 8-30 g/l Ni and/or Co and 0À1- 10 g/l Mg, added as sulphates and/or chlorides, and 3-20 g/l Cl added as alkali metal or ammonium chloride; boric acid and ammonium sulphate may also be added. The anodes may be of Ni and/or Co; or Pt, Ti or graphite with bath replenishment. The pretreatment stages may be all electrolytic, those before metallizing being carried out by the dip, spray or flood method. Electrolytic pickling may be carried out in an acid solution containing 2-25% SO 4 and/or 2-20% PO 4 ions, added as acids, salts or acid salts of alkali metals or Mg. A phosphating treatment, e.g. using a 1-5% solution of magnesium dihydrogen phosphate, may be carried out between the pickling and metallizing stages. Enamelling may be carried out by electrostatic or electro-phoretic deposition, preferably of low oxide frits firing below 760‹ C., e.g. B-Ti white enamel. A pickling mixture for steels is exemplified: 15-20% H 2 SO 4 , 1-3% HNO 3 and 2-4% urea. |
