Tin or tin alloy plating bath, tin salt solution and acid or complexing agent solution for preparing or controlling and making up the plating bath, and electrical and electric components prepared by the use of the plating bath

Abstract

There are provided a tin or tin-base alloy plating bath having significantly improved solderability, a tin salt solution and an acid or complexing agent solution for preparing or controlling and making up the plating bath, as well as electrical and electric components prepared by the use of the plating bath. The plating bath is a tin plating bath or a plating bath of an alloy of tin and one or more metals selected from the following group (I): copper, zinc, silver, indium, gold and bismuth, which bath comprises, as essential components, at least the following components (A) to (D): (A) 5 to 200 g/L of divalent tin ions, (B) one or more acids or complexing agents which form a water-soluble salt or complex with the divalent tin ions, the total amount of the acid(s) or complexing agent(s) being at least stoichiometrically equivalent to the divalent tin ions, (C) one or more metals selected from elements of Groups IB to VB of the fourth to sixth periods of the periodic table of the elements excluding tin, mercury, thallium and elements included in the group (I), the total concentration of the metal(s) being 20 to 2,000 ppm based on tin, and (D) 1 mg/L to 10 g/L of one or more antioxidants.

Dependencies are inferred from the claim text.