| 摘要 |
PURPOSE:To form a good chromate film on the film surface formed by activating the surface of a plating film by immersing the surface of the plating film subjected to a baking treatment into an aq. ammonium salt soln. specified in concn. and pH. CONSTITUTION:The surface of the zinc-iron alloy electroplating film subjected to the baking treatment is immersed into the aq. ammonium salt soln. having 20-150g/l concn. of ammonium ions and 4.0-7.0 pH. An anion which is preferable as the ammonium salt is chlorine ion, fluorine ion, etc., and aq. ammonia or acid is directly added thereto to adjust the pH. A nonionic surface active agent (block polymer of a polyoxyethylene and polyoxypropylene) is added at about 0.1-1g/l to the aq. ammonium salt soln. The surface of the alloy plating is thereby activated and the generation of the uneven colors of the chromate film to be formed on said film and the deterioration in gloss and corrosion resistance are prevented.
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