| 摘要 |
This double-electroplated steel plate has double coated layers, an upper layer and a lower layer, on both surfaces. The lower electroplating layer is composed of a Zn-Ni alloy or a Zn-Fe alloy. The Zn-Ni alloy contains 0.005 to 5 wt.% of one or more compounds chosen from silica, alumina, titanium oxide, magnesia, chromium oxide and zirconium oxide and 10 to 16 wt.% of Ni Ni. The Zn-Fe alloy contains 10 to 30 wt.% of Fe. The upper electroplating layer is composed fo an Fe-B alloy or a high-Fe contg. Fe-Zn alloy. The Fe-B alloy contains 0.001 to 3 wt.% of B. The high-Fe-contg. Fe-Zn alloy contains at least 60 wt.% of Fe. The amt. of the lower electroplating layer is pref. 10 to 50 g/m2 per side. The amt. of the upper electroplating layer is pref. 0.5 to 10 g/m2 per side. |
