The question was: In the IPC standards, e.g. 4553A, "sulfur free" is required for storage of boards. But what is the definition of sulfur free?  



The compounds I'd expect would be of most interest would be sulfur in cardboard/paper or any other storage material. 



-----Original Message-----

From: Brian Ellis [mailto:[log in to unmask]] 

Sent: Wednesday, April 09, 2014 12:39 PM

To: Technet; Greg Munie

Subject: Re: [TN] Definition of Sulfur Free



Surely you mean low sulfide? In fact, mild sulfidisation of silver is not deleterious to solderability and is conductive, to boot. If it's black, then that is too much! Which sulfur compounds do you anticipate it may encounter?



Brian





On 09.04.2014 19:49, Greg Munie wrote:

> Anyone have a working definition of "sulfur free" as it impacts solderability of silver finishes?

>

> As an old chemist I would expect the definition "sulfur free" could have both a concentration and a time a part can be exposed to that concentration before soldering is impacted.

>

> Any thoughts/assistance is appreciated.

>

> Greg Munie Ph.D.

> Director of Design Programs

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