| 摘要 |
PURPOSE:To obtain a blackened steel sheet while easily controlling the color tone by plating a steel sheet with a Zn alloy contg. an Fe group element and by anodizing the plated steel sheet in a soln. contg. anions such as NO3<-> under specified conditions. CONSTITUTION:A steel sheet is finally plated with a Zn alloy contg. >=5wt% Fe group element such as Fe, Ni or Co. The plated steel sheet is anodized in a soln. contg. 1-500g/l NO3<-> and 0.5-300g/l in total of one or more kinds of anions selected among SO4<2->, Cl<->, Br<->, F<->, I<->, CN<-> and PO4<3-> at <=80 deg.C with 10-800 caulomb/dm<2> quantity of electricity to blacken the plated surface. A chromate film contg. about 5-200mg/m<2> Cr and an org. resin film of about 0.2-4mum thickness may be formed successively on the blackened plated surface so as to improve the corrosion resistance.
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