51076

Solder Reflow Problem with nickel underlayer- silver plating  

January 22, 2009

We are facing reflow soldering problem with silver plated component leg. Acc. to our X-RF test , this leg has 57% Copper / 37% Zinc (this must be base) and Nickel (this must be underlayer) and Silver (this must be finishing)

Can anyone help me on this issue?

Kaan Burcak
industry - Manisa, Turkey

There are many things that can contribute to soldering problems. Dirty flux, improper reflow temps, nickel plating thickness too low, nickel plating deposit low in purity. In the soldering process the silver is absorbed in the tin or tin lead layer. Therefore, the nickel purity plays a big role in good solderability. Silver deposit purity is also a concern. I've torn my hair out over the years with periodic solderability failures, so it could be any of the above causes or some I didn't mention. Hope this helps you.

Mark Baker
Fellow Plater - Syracuse, N.Y., USA

I AGREE WITH MARK BUT ALSO YOU NEED TWO IMPORTANT THINGS:
FIRST SILVER PURITY OF 99.9 % ,IF YOU HAVE ANY METALIC BRIGHTNER LIKE ANTIMONY YOU WILL HAVE BIG ROBLEMS IN SOLDERING.
SECOND YOU HAVE TO WASH PERFECTLY THE SILVER AND MAYBE NEUTRALIZE IT ,BECAUSE SOME ORGANICS OF THE BRIGHTNERS COULD INTERFERE WITH THE SOLDER

Ricardo Burstein Interplate Ltd. Bnei Berak, Israel