| 摘要 |
PURPOSE:To obtain a coated film having high performance of the level required in recent years in improving the performance of the electrodeposition coated film by a pretreatment method of a metallic material pretreating the material by a treating soln. of a specific compsn. CONSTITUTION:A treated metallic material which is coated with an aq. dispersible compsn. consisting essentially of A) trivalent and hexavalent Cr compds., B) silica and/or silicate, C) an alkali metallic compd., and contg. 50-75wt% the hexavalent Cr compd. in the component A, in terms of CrO3, 10-100wt% the component B with respect to the component A, and 100:20-100:1 weight ratio between the hexavalent Cr compd. (in terms of CrO3) in the component A and the component C (in terms of hydroxide) and is heat treated at 100-250 deg.C is used as a metallic material in electrodeposition painting of a paint on the metallic material. The corrosion resistance and sticking performance of the electrodeposition paint coated film and further the resistance to filiform corrosion, scab, water sticking, etc. are remarkably improved without deteriorating the electrodeposition paint bath. |
