| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preventing the occurrence of abnormal grains and surplus precipitation in an obtained tin based film when an object to be plated is dipped into a pretreatment liquid, and thereafter, electroless tin based plating is applied. SOLUTION: In the pretreatment to electroless tin based plating, a pretreatment liquid comprising (A) phosphoric acids selected from orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, polyphosphoric acid, hypophosphoric acid, phosphorous acid or their salts, (B) an aliphatic carboxylic acid, and (C) an organic sulfonic acid is prepared, and the object to be plated is dipped into the pretreatment liquid. Since the object to be plated is dipped beforehand into the pretreatment liquid comprising specified phosphoric acids, aliphatic carboxylic acid and organic sulfonic acid, and is then subjected to the electroless tin based plating, by the simple treatment of the dipping, the abnormality in the precipitation of a tinning film or a tin alloy plating film such as a tin-silver alloy and a tin-bismuth alloy can effectively be prevented. COPYRIGHT: (C)2004,JPO
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