METHOD OF DETINNING Sn PLATING LAYER ON Cu-BASED MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a method of detinning a Sn plating layer on a Cu-based material, by which a Sn layer and a CuSn layer and the like of a Cu-based material with the Sn plating layer containing the Sn layer and/or the CuSn layer can be easily subjected to detinning even when machining oil or the like is adhering thereto, and the Cu-based material can be recycled as a raw material.;SOLUTION: A Cu-based material 5 is immersed into an alkali hydroxide aqueous solution 10 with a concentration of 3.0 to 37.5 mass%, and a H₂O₂ aqueous solution with a concentration of 3.0 to 50.0 mass% is added into in the alkali hydroxide aqueous solution. The temperature of the alkali hydroxide aqueous solution 10 when the Cu-based material 5 is immersed ranges from 60 to 105°C. A ratio A/B, wherein A and B represent molar numbers of the alkali hydroxide in the alkali hydroxide aqueous solution 10 and of H₂O₂ in the H₂O₂ aqueous solution, respectively, is not less than 10. The molar numbers C and D of Sn in the Sn layer and of Sn in the CuSn layer, respectively, satisfy B≥C×2+D×6.;COPYRIGHT: (C)2011,JPO&INPIT