Electronics Forum | Fri Aug 22 09:07:22 EDT 2008 | blnorman
Sulfur is probably the culprit. Board supplier should be providing boards with anti-tarnish sheets between the individual boards. Also, cardboard is a major source of sulfur and so boards should not be shipped in cardboard.
Electronics Forum | Mon Aug 04 12:38:25 EDT 2008 | blnorman
Avoid cardboard boxes as well. They are sulfur bearers, and silver has an affinity to form silver sulfide.
Electronics Forum | Tue Nov 29 17:18:26 EST 2022 | davef
Yes, electronics manufacturing is a volume producer of cardboard waste. If the components are ESD-critical, cardboard and most plastics are not ESD safe. Static charges can be generated on these materials during handling by the friction of dissimila
Electronics Forum | Mon Apr 26 14:40:07 EDT 2010 | blnorman
We had one product that used immersion silver plating. There were a couple of instances where we saw tarnishing, and elemental analysis confirmed the presence of sulfur. These boards did have the anti-tarnish sheets between boards, but somehow they
Electronics Forum | Sun Feb 23 14:32:42 EST 2003 | davef
Sources of sulphur in PCB fabrication are: * Some locales have high H2S concentrations in the air. * Metal etching steps that use sulfuric acid or a sulfonated buffering compound may result in sulfate residues. * Sulfates can come from contact with
Electronics Forum | Thu Sep 27 19:52:28 EDT 2001 | davef
All of the discussion of "environmental controls" are a matter of degree, dependent on the requirements of the product that you manufacture. For example: shops assembling under-the-hood products have different requirements than shops making garage d
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