Electronics Forum | Fri Feb 21 20:41:32 EST 2003 | Raul
It is a common knowledge that sulphur and immersion silver finish on a PCB do not go together very well. We are seeing peaks of sulphur on some of our assemblies (with silver finish) and as expected we experience severe difficulties with processing t
Electronics Forum | Fri Feb 23 16:11:51 EST 2001 | Dave E
The sulphur outgassing from these rubber bands was >enough to contaminate every board... Well, if every rubber band is a threat then sulphur contamination must be a common problem. Are sulphur test kits available?
Electronics Forum | Fri Aug 30 11:53:12 EDT 2002 | genny
Possibly this is tarnish? Silver finish requires a bit more care in handling or packaging - to avoid contact with sulphur which may cause tarnish. Some cardboard boxes gas out enough sulphur to cause a problem. Possibly look at your method of stora
Electronics Forum | Mon Feb 26 09:36:08 EST 2001 | blnorman
ASTM E 443 is a test for sulfur by Oxygen Flask Combustion. Other instruments will detect sulfur (I assume a SEM with EDS capability will pick up the sulfur). We had an addition cure silicone potting compound inhibition problem last year that was t
Electronics Forum | Wed Apr 20 08:06:21 EDT 2005 | davef
We'd reject the boards because: * Vacuum seal is punctured. * HIC is expired. One of the nice things about immersion coatings is that the fab can rework the coating. You cannot do that with other coatings. Finally, every HIC that we investigated c
Electronics Forum | Fri Aug 10 13:46:30 EDT 2012 | lrota
I would check the IPC spec IPC-1601 ( Printed Board Handling And Storage Guideline). Also, be sure your dessicant does NOT contain sulphur in either the dessicant material or the paper holding the material. Enthone advises to not use dessicants ins
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 | Fri Feb 23 10:24:24 EST 2001 | johnthor
We still build a legacy product with a primitive backplane using silver plated fork terminals for outside world connections. After some 20 years of no problems the fork terminals on raw stock PCBs were black and almost unsolderable. Because of the
Electronics Forum | Sun Jul 29 09:17:20 EDT 2001 | davef
Tough to say, but ... Chlorine: Many fluxes contain chlorine. Sulphur: Many solders and paper packing materials contain sulphur. Sodium: No idea. IPC-J-001 talks to board cleanliness and specifies criteria according to the cleanliness test met
Electronics Forum | Sat Aug 23 08:43:32 EDT 2008 | davef
Ugh, there are more reasons that immersion silver [IAg] to go yellowish than pigs at the county fair. That aside, sulphur is one of the reasons, as you say. The sulphur can be from a variety of sources, such as: * Pollution in the air * Ill advised p
