Michael,

It was my understanding the low to mid-phosphorus nickels (3-6%, 6-9%) were better for soldering, whereas high-phos (9-12%) nickels were better for corrosion resisitance.

In either case, won't the solder at the solder/nickel interface always be 'high' in phos, with the potential for bad intermetallics being present.

    However, I defer to the plating guru's of the forum.

Steve Creswick - Gentex Corp


-----Original Message-----
From: Michael Forrester [mailto:[log in to unmask]]
Sent: Friday, July 25, 2003 10:19 AM
To: [log in to unmask]
Subject: [TN] % Phosphorus In Nickel deposit


Is there a specification for the % phosphorous in the nickel deposit for
electroless
Nickel/Immersion Gold for surface mount pads on PWBs?  We are seeing as
high as 14% and are also seeing solder joint failures at the nickel
interface on
BGAs w/18mil balls.  Is there an industry standard for phosphorous content?
If there is no industry standard, any ideas of what the spec should be?
Thank you.

Best Regards,

Mike Forrester
LeCroy Corp.

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