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Date: | Fri, 20 Oct 95 16:33:22 PST |
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David,
The only test I am aware of involves nitric acid vapor and
eletrographics. Insure your gold plating is within 5-10 millionths
and never greater than 50 millonths. Any less than 5 millionths Au
with improper immersion plating will cause the Au to be porous,
in-turn, oxidizing underlying copper and not allowing the flux to
properly clean. A high Au concentration, greater than 50 millionths,
causes poor bond strength.
The concern of porosity should not be a concern, since millions of
SIMMS, DIMMS and bareboards go into products every day with no contact
problems. If you are using NiAu as an alternative surface finish,
I've conducted several ineternal environmental tests with NiAu, OSP
and HASL with no problems. If you are having problems with
conductivity at the connector region, investigate the connector or the
PCB supplier and set in place the above recommendation.
If it still concerns you; 2 pores per contact tab on 10% of the
contact tabs, and no more than 1 pore on each of the remaining tabs
(BS 9762)
or reference
IEC-326 and prepare to discuss porisity in-depth with your chosen
vendor.
______________________________ Reply Separator _________________________________
Subject: Plating specification
Author: [log in to unmask] at halsic_ccsmtp
Date: 10/19/95 11:20 AM
There are plating specifications and test methods for gold over nickel
plating on printed circuit board edge connectors. Verifying plating
thickness is straight forward but what pass/fail criteria are used in the
industry for porosity of gold over nickel? How many pores per CM*CM are allowed?
Any sources of information/specifications would be appreciated.
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* David Hamilton Ph: 334-283-7377
* Manager of Electronics FAX: 334-283-7293
* Schlumberger Water Division Email: [log in to unmask]
* Hwy 229 South
* Tallassee, Al. 36078
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