| 摘要 |
PURPOSE:To obtain a titled electroplated steel plate of which the non-plated surface has excellent chemical convertibility by forming an extra thin plating layer of a Zn-Ni alloy on the opposite side of the steel plate where plating is not required then dissolving preferentially the Zn on the plated layer and subjecting the steel plate to Zn-Ni alloy electroplating on the one side. CONSTITUTION:A Zn-Zi alloy contg., for example, about 13% Ni content is plated on a steel strip at a prescribed coating weight by using a sulfuric acid bath kept at 1.8pH and 55 deg.C and thereafter the strip is dipped in the plating bath without conducting electricity thereto. An extrathin plating layer of the Zn-Ni alloy is also formed on the opposite side where plating is not required, then the strip is passed through the succeeding bath. The Zn on the side requiring no plating is preferentially dissolved during the passage and an Ni-rich layer having finally 30-2,000mg/m<2> coating weight is formed thereon upon completion of the passage. As a result, the contamination during the plating treatment of the non-plated surface is prevented and the one side Nn-Ni alloy electroplated steel plate having improved chemical convertibility is obtd.
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