| 摘要 |
PURPOSE:To enhance the secondary adhesive strength of the unplated surface of a steel plate to a coated film, by coating an aqueous soln. contg. Ti ions and Fe, Co or Ni ions on the steel plate immediately before phosphating the plate. CONSTITUTION:An aqueous soln. contg. 1-100ppm (A) Ti ions and 1-100ppm (B) in total of ions of one or more among Fe, Co and Ni and satisfying A+B>= 6ppm is coated on a zinc-plated steel plate or the like immediately before phosphating the plate. By the pretreatment before the chemical conversion treatment, the effect of the resulting phosphate film is enhanced, and the secondary adhesive strength of the unplated surface subjected to the double coating is enhanced. |
