Electronics Forum | Mon Jun 25 03:52:24 EDT 2012 | awtm
Our Customer had detected tarnished pad on ImAg PCBA and had conducted several SEM-EDX test at the soldermask below some of the chip resistors. High concentration of sulfur was found and it can be significantly reduced after further chemical cleaned
Electronics Forum | Mon Jun 25 11:33:20 EDT 2012 | davef
The immersion silver is an active surface and readily combines with sulfur from the environment. Silver sulfide tarnishes the surface and creates doubt about the integrity of the finish at inspection. [uyemura.com/library-4.htm] Your customer's boar
Electronics Forum | Wed Sep 03 11:42:21 EDT 2008 | robinj
If the tarnish is really dark, it is very difficult to remove. Since it is yellowish it is only in the early stages. Replating will definitely work. I have used sulfuric acid based cleaners to remove this yellowish color. But rinse well and dry quick
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 Jan 17 14:52:17 EST 2008 | gnath
All, Can someone help find a source for purchasing interleaving/packaging paper for Immersion Silver boards (sulfur free + ph neutral ..). Thank you!
Electronics Forum | Thu Jul 26 23:52:24 EDT 2007 | gioblast
HI..anyone who can give me a link to enlighten me on this plating for pb-free..Most people say this is the same? ARe they really? or different in process?? ..Any info on best storage for this plating? I have read all those stuff like avoiding sulfuri
Electronics Forum | Mon Feb 20 16:31:09 EST 2006 | GS
Hello Gents, ..............several questions about the subject: Q1)Are there any standard regulating the subject ? Very few infos found on IPC. Q2)Which materials are suggested to seal (Bag) the PCB ? Q3)Is it necessary the vacuum sealed bag ? if
Electronics Forum | Wed Feb 22 08:31:42 EST 2006 | davef
Q1 Are there any standard regulating the subject? Very few infos found on IPC. A1 We�re unaware of standards for packing and storage for most types of boards. * IPC 4553 standard for Immersion Silver Finish, 3.8 Packing and Storage. * J-STD-033 and E
Electronics Forum | Thu Sep 03 12:03:52 EDT 2009 | Sean
Hi All, I have few questions about creeping corrosion that potentially happen on lead free immersion silver PCB as below: 1) What test that we can conducted to verify whether the failure we seen is due to creeping corrosion? 2) I heard that lead fr
Electronics Forum | Tue May 21 20:27:05 EDT 2002 | davef
No N2. We could not fix a benefit for N2 in our minds. Just fold the excess bag material over to expell most air and then seal the bag. [Have you assessed the benefit of N2?] F Monette can tell you stories about little versus more pressure. If he
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