ZINC PHOSPHATE SERIES CHEMICAL CONVERTION TREATING METHOD FOR ALUMINUM OR ALUMINUM ALLOY AND COMPOSITION FOR ZINC PHOSPHATE SERIES CHEMICAL CONVERTION TREATMENT

摘要

PROBLEM TO BE SOLVED: To provide a zinc phosphate series chemical convertion treating soln. capable of continuously treating a large quantity of aluminum or aluminum alloy and to provide a zinc phosphate series chemical convertion treating method. ;SOLUTION: By supplying a composition A contg. phosphoric acid ions, nitric acid ions and zinc ions, and in which the molar ratio of zinc ions/ phosphoric acid ions is regulated to 0.7 to 1.3 and a composition B contg. sodium ions and fluorine ions, and in which the molar ratio of sodium ions/fluorine ions is regulated to 0.6 to 1.0, a zinc phosphate series treating soln. contg. phosphoric acid ions, nitric acid ions, zinc ions, sodium ions and fluorine ions in which the concn. of phosphoric acid ions and the concn. of fluorine are held to desired value is used. For the measurement of the concn. of phosphoric acid, an alkali neutralization titration method can be used, and for the measurement of the concn. of fluorine, current value flowing between a silicon electrode and an inert electrode can be used.;COPYRIGHT: (C)1998,JPO