| 摘要 |
PROBLEM TO BE SOLVED: To develop and provide a discoloration prevention/treatment agent effective for a lead-free plating film instead of sodium phosphate solution treatment. SOLUTION: The discoloration in the surface of tin or a tin alloy can be extremely effectively prevented by using a discoloration preventing agent composition obtained by incorporating one or more kinds selected from heterocyclic nitrogen-containing compounds or the salts thereof, aliphatic or aromatic amines and 6 to 24C straight chain or branched aliphatic carboxylic acids or the salts between the carboxylic acids and the amines into a solution comprising one or more kinds selected from compounds containing amino nitrogen having two or more methylene groups to which phosphonic acid groups are bonded, and whose solution pH is controlled to an acidic region of pH≤7. COPYRIGHT: (C)2007,JPO&INPIT
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