| 摘要 |
<p>PROBLEM TO BE SOLVED: To form a tin coating uniformly on a plated body by a contact type electroless tin plating system using zinc.SOLUTION: There is provided a contact type electroless tin plating method including: dipping a plated body in an acid electroless tin plating bath containing (A) soluble first tin salt, (B) zinc metal, (C) a complexing agent such as oxycarbonic acids and amino carboxylic acids, and (D) a surface active agent selected between a cationic surface active agent and an ampholytic surface active agent so as to bring (B) the zinc metal and the plated body into contact with each other; and supplying electrons generated by dissolution of zinc to divalent tin ions through the plated body so as to precipitate tin on the plated body. A specific complexing agent (oxycarbonic acids etc.) for divalent tin ions and a specific kind of surface active agent coexist, and then the divalent tin ions are stabilized in the bath and transfer of the electrons from zinc to the tin ions on the plated body is accelerated, so that the metal tin is smoothly precipitated on the plated body.</p> |
