Electroplating bath containing citric acid or citrate for tin or tin alloy plating

摘要

A brightener is added in the ratio of 0.5-5 g per 1 l of electric plating bath of pH 4-8 containing citric acid or citrate for tin or tin alloy plating. The brightener contains a water soluble reaction product obtained by reacting polyamine such as pentaethylenehexamine, aliphatic aldehyde such as formaldehyde, and aromatic carboxylic acid such as methyl benzoate.