| 摘要 |
PURPOSE:To obtain a product treated by chemical conversion having excellent corrosion resistance and appearance by subjecting the zinc or zinc plated products prior to chemical conversion treatment to surface treatment with an alkaline soln. contg. the specific amount of hydrogen peroxide. CONSTITUTION:Zinc or zinc plated products forms an inert film of oxide on their surfaces and this retards the formation of film at the time of chemical conversion treatment. This retarding effect is eliminated by treating the surface with an alkaline soln. contg. 0.3-10.2g/l hydrogen peroxide. Namely, as shown by the equations, zinc oxide (ZnO) is first peroxidized by the hydrogen peroxide (H2O2) in the soln. so that ZnO is made extremely easy to dissolve in the alkaline soln., whereby the subsequent reaction owing to the coordination of hydroxyl ions is accelerated and quick dissolution is made possible. As a result, the inert film on the product surfaces dissolves with good reactivity over the entire region, and activate the surfaces by assuring good surface shapes; moreover, a superior chemical conversion film is formed. |
