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| From [log in to unmask] Wed Jun 5 11: |
13:35 1996 |
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Jack Tippit wrote:
We have instances where tin/lead coated pins are inserted into gold plated
sockets, etc. Components even have gold/tin-lead or gold/tin interfaces,
such as an IC socket with a gold contact with a tin sleeve. Mil-Std-889B
indicates gold as being incompatable with tin or tin/lead. Has anyone
looked into this issue and is there a potential for corrosion formation and
associated problems? Again, I just refereing to mechanical contact ( not
soldering ).
WE HAVE HAD A PROBLEM WHERE A PIN GRID ARRAY PART THAT HAD GOLD LEADS CAME IN
SOLDER DIPPED AND WHEN INSERTED INTO THE GOLD SOCKET, DEVELOPED FAILURES IN THE
FIELD THAT OUR FAILURE ANALYSIS CONTRIBUTED TO "FRETTING CORROSION". WE HAD A
LARGE QUANTITY OF THESE PGA ASIC'S, SO HAD TO MODIFY THE ASSEMBLY PROCESS TO USE
THEM UP; NOT EXPOSE TO FLUX, MOISTURE, ADD BAKING STEPS, ETC.
CINDY KEMP
LOCKHEED MARTIN CORP.
ORLANDO, FL
407-826-6873
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