| 摘要 |
PURPOSE:To produce treatment liquid capable of forming a high-degree black film on the surface of zinc at a short time by preparing an aq. soln. wherein both respective metallic ions of Ag, Sb, Cu, Bi and respective metallic ions of Ni, Fe, Co are incorporated at specified amount in a specified ratio and pH is specified. CONSTITUTION:The following treatment liquid is prepared wherein two or more kinds of metallic ions (a) selected from among Ag ion, Sb ion, Cu ion and Bi ion are contained at >=0.05g/l respectively and contained at 0.18-20g/l as all amounts and one or two or more kinds of metallic ions (b) selected from among Ni ion, Fe ion and Co ion are contained at 1-100g/l as total amount and also molar ratio (b/a) of both metallic ions is 0.18-1,900 and pH is regulat ed to 0.5-7. When using this treatment liquid and subjecting zinc or zinc alloy to blackening treatment at about 30-80 deg.C, a good black film is stably formed in several sec - about 10sec.
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