摘要 |
<p>By using a zinc-phosphating solution, which does not contain a nickel ion, but contains 0.1 to 4 g/l of a cobalt ion, 0.1 to 3 g/l of a manganese ion, a phosphating accelerator, 200 to 500 mg/l of a simple fluoride compound in terms of HF concentration and a complex fluoride compound in a mole ratio of 0.01 to 0.5 relative to the simple fluoride compound, a zinc phosphate coating film suitable for cationic electrodeposition coating and superior in coating film adhesiveness and corrosion resistance, especially in warm brine resistance and scab resistance, is formed on the metal surface simultaneously having an iron-based, a zinc-based and an aluminum-based surface by using an identical solution.</p> |