| 摘要 |
PURPOSE: A chromate coating film is prepared which has a reduced specific resistance and a continuous weldability. CONSTITUTION: Chromate coating film is formed on the zinc coated steel plate and washed by a solution containing 5-50 g/l of cobalt ion from cobalt nitrate to give a chromate coating film. Thus, zinc coated steel plate having 20 g/cubic meter of zinc is cut to 300X300 mm size, coated by a reactive chromate solution containing 1.0- 3.3 g/l of T-Cr, 5.0-10.0 g/l of nitrate group, 3.0-10.0 g/l of sulfate to give a chromate coating film having 5- 100 g/l of chrome, followed by washing with a solution having 5- 100 g/l of cobalt ion.
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