Aqueous solution for blackening metal surface and blackening treatment method

摘要

PROBLEM TO BE SOLVED: To provide a new aqueous solution for blackening of a metal surface and a new blackening method.SOLUTION: An aqueous solution for blackening of a metal surface contains the following (A) and (B) components. (A) component: at least one selected from the group consisting of fluoride ions, borofluoride ions and silicofluoride ions. (B) component: at least one selected from amino acids and derivatives thereof, pyridine derivatives, and pyrrolidone polymers.SELECTED DRAWING: None