ELECTROLYTIC PHOSPHATE SALT CHEMICAL CONVERSION TREATMENT BATH COMPOSITION AND PHOSPHATE SALT CHEMICAL CONVERSION TREATMENT METHOD

摘要

[Problem] To verify reaction-constituting reactions for an electrolytic phosphate salt chemical conversion treatment in detail to establish a more accurate and more rational reaction system, whereby it becomes possible for the phosphate salt chemical conversion treatment reaction to proceed more rapidly or it also becomes possible to stabilize a coating film produced by the reaction and reduce the variation of the coating film.[Solution] An electrolytic phosphate salt chemical conversion treatment bath composition for use in an electrolytic phosphate salt chemical conversion treatment, said composition being characterized in that "a conjugate of phosphoric acid and zinc" and nitric acid are contained, a metal component ion that does not serve as a coating film component is not contained substantially, and the content ratio of active phosphoric acid in "all of phosphoric acid components", i.e., the whole phosphoric acid component system composed of the "active phosphoric acid" and "phosphoric acid that is a component for the conjugate of phosphoric acid and zinc" is 0 to 10% (by mass) or less.