| 摘要 |
<p>The surface of galvanized sheet iron is coated with a water-base chromate treatment prepared by adding sulfate ions, nitrate and/or hydrofluoride ions and metallic ions such as Co, Ni, Sn, Cu, Fe and/or Pb to an aqueous solution containing 4.0 to 51.0 g/l of Cr (VI), 6.0 to 38.0 g/l of Cr (III) and 0.5 to 97.0 g/l of phosphate ions and having a Cr (III) to Cr (VI) ratio of 0.2 to 1.4 by weight, and the coated surface is dried without washing with water to form thereon a chromatic coating in a coating weight of 20 to 160 mg/m2 in terms of chromium.</p> |
