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 | Wed Aug 27 18:28:29 EDT 2008 | blnorman
We have an immersion silver board that has a brown discoloration after processing. It's not flux residue, that normally doesn't cause this condition. Elemental analysis shows less than 1% sulfur, and I thought silver sulfide is more a black color.
Electronics Forum | Fri Aug 22 10:01:52 EDT 2008 | robinj
I have seen this problem before. If the color is yellow usually it is caused by moisture left on the boards from poor drying after immersion silver. One of the ways to get rid of this is by dipping in acid cleaner solution. If the board supplier uses
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 | 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
Electronics Forum | Fri Aug 30 16:25:21 EDT 2002 | davef
Imm silver holds-up to multiple thermal cycles very well. The things, we guess, are happening to make imm silver tough to solder after heating and sitting are: * Oxidation of the silver. * Reduction of the co-deposited organic anti-tarnish [used in
Electronics Forum | Fri Jan 11 17:14:13 EST 2002 | davef
We have one product with electroless nickel, immersion silver solderability protection. We do not purport to be experts, but like many things, have seemingly boundless opinions. Side note: There are a least three different [maybe five] imm silver
Electronics Forum | Thu May 09 17:13:10 EDT 2002 | davef
We are converting all our ENIG to imm silver. CHARACTERISTICS * Nominal thickness of the deposit will be 0.1 to 0.3 microns. * Deposit is flat and uniform * It will withstand multiple heat cycles in assembly, which can be problematic with tradition
| 1 |
