Another point to consider is the hardness of the gold. Electroplated gold is
usually alloyed with Co and is called "hard" gold. Most gold flashes are
performed with an electroless process and do not have the Co alloy and are
therefore much softer. So, be aware that going from 30uin of hard gold to 7uin
of soft gold is a big step. (I think that the porosity characteristics of the
immersion process are worse than electroplate, but that needs verification -
comments?)
That being said, there is a big push to make the flash finish work in the place
of the standard 30uin plating. In some applications with little wear and mild
office type environments, the flash may be OK, depending on the mating
connector, thermal cycling characteristics, etc. My take on the issue is that
it is acceptable in certain applications, but definitely OK the use of flash on
an application specific basis, and after a well thought out qualification plan.
After all, the quality of the product is our (the engineer's) responsibility,
not the board vendor.
Rod Martens
Hewlett-Packard
______________________________ Reply Separator _________________________________
Subject: Re: [TN] Gold Flash vs Gold Plate on PCB connector Fingers
Author: Non-HP-ddhillma ([log in to unmask]) at
HP-ColSprings,mimegw4
Date: 3/11/98 6:23 AM
Hi Kathy - I just recieved the following reference (thanks to whoever
mentioned it in a TechNet response!) which you may find helpful:
"Survey of Contact Fretting in Electrical Connnectors", M. Antler, IEEE
Transactions on Components, Hybrids, and Manufacturing Technology, Vol.
CHMT-8, No. 1, March 1985
It doesn't address flash gold specifically but contains a great deal of
info on issues you are facing. Good Luck.
Dave Hillman
Rockwell Collins
[log in to unmask]
[log in to unmask] on 03/10/98 06:23:22 PM
Please respond to [log in to unmask]; Please respond to
[log in to unmask]
To: [log in to unmask]
cc: (bcc: David D Hillman/CedarRapids/Collins/Rockwell)
Subject: [TN] Gold Flash vs Gold Plate on PCB connector Fingers
Hey everyone. Can anyone help me out here? Our board vendor is trying
to convince our purchasing department to use gold flash (about 7u"
thick) on the PCB connector fingers instead of gold plate (about 30u"
thick). We make memory boards. These boards will most likely be
plugged in to a system one time, however there could be instances where
they are installed and removed many times. We guarantee our boards for
life. Won't the gold flake off, exposing the nickel and eventually
cause opens if the nickel surface starts to oxidize? Could anyone tell
me where I can find documented proof which supports this theory?
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