| 摘要 |
PURPOSE: A Sn-Zn based alloy electroplating solution having superior corrosion resistance and surface roughness is provided to obtain a coated strip having superior corrosion resistance, forming property and surface roughness by appropriately controlling composition of the plating solution using Sn-Zn-Co or Sn-Zn-Zr alloy plating solution. CONSTITUTION: The Sn-Zn based alloy plating solution comprises 15 to 40 g/L of tin chloride (SnCl2·2H2O), 10 to 50 g/L of zinc sulfate (ZnSO4·7H2O), one element selected from the group consisting of cobalt and zirconium, 40 to 150 g/L of trisodium citrate dihydrate (Na3C6H5O7), 10 to 80 g/L of potassium tartrate (K2C4H4O6·1/2H2O) and 30 to 90 g/L of ammonium sulfate {(NH4)2SO4}, wherein a weight ratio of cobalt to tin is 1:0.02 to 0.05, and a weight ratio of zirconium to tin is 1:0.05 to 0.10, and wherein the cobalt is cobalt sulfate (CoSO4·7H2O), and the zirconium is one compound selected from the group consisting of ammonium zirconate, hexafluorozirconium and sodium hexazirconium.
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