ZINC OR ZINC ALLOY BLACKENING SOLUTION AND BLACKENING METHOD

摘要

PURPOSE:To obtain a blackening soln. giving high blackness to Zn or a Zn alloy by treatment for a short time by preparing an aqueous soln. of a specified pH contg. specified amounts of Ag ions and ions of a metal such as Ni in a specified molar ratio. CONSTITUTION:An aqueous soln. of 0.5-7 pH contg. 0.5-20g/l Ag ions and 1-100g/l ions of one or more kinds of metals selected among Ni, Fe and Co in 0.18-3,700 molar ratio of the metal ions to Ag ions is prepd. silver sulfate or silver nitrate may be used as an Ag ion source. Nickel carbonate may be used as a Ni ion source, ferrous nitrate as an Fe ion source and cobalt carbonate as a Co ion source. When the surface of Zn or a Zn alloy is treated with the aqueous soln. for a short time, a stable black film having high-grade appearance is formed.