防止锡回流变色的连接器电镀工艺

分析了连接器锡镀层发生回流变色的原因。开发了一种能有效地控制连接器表面锡的回流变色和锡须形成的新工艺。该工艺能形成较大的结晶粒度,并能控制结晶取向从而获得光亮的外表。采用在镍层表面再电镀一层镍磷合金形成N i/N i-P双层镀层的方法,改善了镍层表面纯锡的回流变色问题。最后采用与常规碱式后处理有很大差别的酸式后处理方法对锡层表面进行处理。新工艺有效地解决了连接器表面纯锡的回流变色问题,实现了工业化生产。

Electroplating technics on connector for prevention of tin reflow discoloration

The reasons of reflow discoloration of tin deposit on connector were analyzed.A kind of new technics that effectively controls reflow discoloration of tin deposit and whisker formation on connectors has been developed,which gives relatively large grains but in which the grain orientations are controlled to give a bright appearance.A significant improvement in tin reflow discoloration on nickel is obtained by using an electrolytic nickel-phosphorus overplate to form a duplex nickel/nickel-phosphorus layer.Finally,the tin surface is treated by applying an acidic post-treatment method that is very different from the conventional alkaline post-treatment method.The problem of pure tin deposit reflow discoloration on connector was solved effectively with the new technics,which has been put into industrial production.