Electronics Forum | Tue Feb 27 18:16:42 EST 2001 | davef
I have never seen excess tin [heard of it, just never seen it]. Excess lead yes, but tin no. See, tin oxidizes faster than lead. This means that dross has a higher tin content than the solder in the pot. So, with a very high dross machine, we regul
Electronics Forum | Mon Dec 12 14:04:33 EST 2005 | craigj
Hi All was wondering is there anything I should be aware of or look out for if using parts with SnBi (Pb free) lead plating with Sn/Pb/Ag solder paste? I was always lead to believe that mixng lead and bismuth caused problems or are the bismuth levels
Electronics Forum | Mon Dec 12 15:57:58 EST 2005 | Samir Nagaheenanajar
4% of the alloy), there is a ternerary phase (not sure if i spelled that right) where the melting point of the alloy is MUCH less than, say, SAC305's. Sn-Bi has also been associated with...... none other than Tin Whiskers. There are some in the in
Electronics Forum | Tue Dec 13 09:15:56 EST 2005 | Samir Nagaheenanajar
5% Bi results in less plasticity * Formation of low temperature (ternerary phases) not detected. I don't advocate the use of Bismuth, per se, but rather I'm just relaying info. that I learned this from a Lead-Free seminar that I attended at Riyadh
Electronics Forum | Mon Dec 12 21:38:05 EST 2005 | davef
Effect of lead on bismuth solders * Lead from hot air leveling (HAL) coatings can diffuse through the grain boundaries of the alloy. * Lead can form a eutectic composition of Bi52Pb32Sn16 in the grain boundaries. * Melting point of this eutectic all
Electronics Forum | Tue Dec 13 14:55:12 EST 2005 | muse95
Your response is from the point of view of using a Bismuth solder with Pb plated leads. Samir's point of view is from Bismuth in the plating on the leads being used with a Pb solder. There is a very large difference in the amount of Bi that will en
Electronics Forum | Tue Feb 08 22:04:34 EST 2005 | davef
Tough to say. Can you accept the loss of strength of your solder connection if upto 2% of the solder is affected? * Lead and bismuth alloys can form a eutectic composition of Bi52Pb32Sn16 in the grain boundaries. * Melting point of the eutectic all
Electronics Forum | Wed Aug 09 08:06:07 EDT 2006 | davef
See "IPC-4554 Specification for Immersion Tin Plating for Printed Circuit Boards" 3.2.1 Immersion Tin Thickness. The most common reason for solderability issues with the white tin surface coating during multiple thermal excursions is a thin white ti
Electronics Forum | Mon Aug 07 09:04:09 EDT 2006 | molos21
Hi everyone, I am starting to use the lead free process and I had a few wetting problems (solder did not reach top side) at the wave soldering process once the pcb had passed our smt line (one heat pass). From what I understand, I have had a problem
Electronics Forum | Wed Jul 29 13:44:45 EDT 1998 | David Spilker
We are investigating alternatives to HASL finishes for more dense PWBs. OSP is not a good choice because of low solid flux and possibly long shelf life. Immersion gold is expensive and so far has been more difficult to wave solder. Has anyone had
