| 摘要 |
PURPOSE: To conduct Zn-Ni alloy plating at a low cost at the time of electroplating a Zn-Ni alloy using an insoluble anode by separately installing a Zn dissolution tank for replenishing Zn ion to a plating soln. CONSTITUTION: A steel sheet as a cathode and an anode insoluble in a plating soln. are dipped in a Zn-Ni alloy plating soln., and a current is applied to electroplate the steel sheet with Zn-Ni alloy. In this case, a vessel contg. metallic Zn is installed to replenish the consumption of Zn ion in the plating soln., the plating soln. is circulated to dissolve the metallic Zn, and Zn ion is replenished until a normal concn. is obtd. When the maximum length of the metallic Zn to be used is denoted by A(cm), the minimum length by B(m), the cross-sectional area of the dissolution tank by S(m<2> ) and the flow rate of the plating soln. passing through the dissolution tank by V(m<3> /min), V>=30×(A/B)×S×A<0.5> when B/A>=0.25, and V>=120×S×A<0.5> when B/A<0.25. Since the V is adjusted in this way, Zn ion is perfectly replenished, and the steel sheet is efficiently plated with Zn-Ni alloy.
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