| 摘要 |
PURPOSE:To enhance the oxidation preventing effect of an antioxidant for preventing the oxidation of tin ions in a soln. by using a specified heterocyclic compd., a deriv. thereof, specified dihydroxynaphthalene or a deriv. thereof. CONSTITUTION:This antioxidant is composed of one or more among a heterocyclic compd. having an N atom in a ring and an OR group bonding to the hetero ring, a deriv. thereof, 1,4- or 1,7-dihydroxynaphthalene and a deriv. thereof. The heterocyclic compd. may be 8-oxyquinoline or 2-methyl-8-hydroxyquinoline. Since the antioxidant is very effective in preventing the oxidation of bivalent tin ions to quatervalent tin ions, a soln. contg. tin ions such as a tin or tin alloy plating soln. is highly stabilized by adding the antioxidant to the soln. |
