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Fri, 31 Jul 1998 09:55:18 -0700 |
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I have seen recent postings expressing concern about the possible
detrimental effect on solder joint life caused by the phosporous in
traditional electroless (autocatalytic) nickel formulations. I am
curious about whether anyone has looked into the new boron
formulations (e.g., ASTM B607) as a possible alternative.
Boron is a good metal deoxidizer and forms more stable oxides
than phosphorous. Perhaps this will make it a more stable component
of solder joints. The intermetallic compounds it forms (called
borides) have some unusual electronic properties (see Cotton and
Wilkinson, Advanced Inorganic Chemistry, 5th ed. p165-166). At least
two nickel intermetallics are listed: Ni3B and Ni4B3.
I hope this helps.
Pat Hogue
Materials and Processes Engineering
Honeywell Inc
Satellite Systems Operation
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