| abstract |
A chemical treatment method in which an object to be treated is treated with a chemical treating agent to form a chemical conversion coating, wherein the object to be treated comprises at least one aluminum-plated steel sheet and at least one member selected from the group consisting of cold-rolled steel sheets, zinc-plated steel sheets, and aluminum sheets and the chemical treating agent is one which comprises zirconium, fluorine, and an aminated silane coupling agent and in which the zirconium content is 100-700 ppm in terms of metal amount and the fluorine/zirconium ratio is 3.5-7.0 by mole. According to the method, a sufficient coating amount can be ensured on the surface of a zinc deposit, cold-rolled steel sheet, zinc-plated steel sheet, aluminum-plated steel sheet, or the like and a chemical conversion coating having sufficient base-hiding properties and sufficient adhesion can be formed. |