If it is on wipe zone, you might have porous gold plating or thin gold plating layers. Or some one used soft gold instead (used left over soft gold platingbath for connector as a cheap way. Instead of real hardening gold with Ni, Co.
--------------------------
Sent using BlackBerry
----- Original Message -----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Wednesday, February 29, 2012 01:01 PM
To: [log in to unmask] <[log in to unmask]>
Subject: Re: [TN] Field Return Product w/corrosion product
All fluxes, by definition, must have some form of corrosive ion for it
to be able to reduce metal oxides. Even pure rosin isomers have a
carboxylic acid group. From your description, it seems probable that you
have what is effectively a short-circuited battery with gold and copper
as your electrodes with bare copper where the fingers are cut or the
gold plating is too thin/porous/worn through. Any condensation would
provide you with an electrolyte, exacerbated by tthe presence of any
ionogenic and/or hygroscopic contaminant (not necessarily from your
flux, which you don't want on gold-plated fingers, anyway).
Brian
On 29/02/2012 16:53, Victor Hernandez wrote:
> Fellow TechNetters;
>
> Do No Clean LF fluxes, Rosin Core/molten solder, have a corrosive ion? Every so often when conducting analysis on Field Return Product I notice small amount of corrosion product on gold plated contact on DIMM and PCI Slot connector. Sometimes on other gold plated connector leads. So I am trying to understand which component had a corrosive ion waiting for the right conditions to flourish. Small amount of greenish/bluish residue. It can be seen on wipe zone and/or stamp edge of contact. Where is this active corrosive ion coming from?
>
> Can someone provide the link to Stevezea home page for posting pictures?
>
> Victor,
>
>
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