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How to prevent silver from sulfur impact?

 

Hello all,

I've experienced a silver tarnish problem with silver-plated lead-frame which is confirmed to be caused by sulfur contaminant in atmospheric air. My questions are as below:

1. Is there any absorbent can be used to specifically absorb sulfur-containing compound like H2S and SO2 in air?
2. What level of H2S or SO2 is required to cause silver tarnish?
3. Is there any industrial standard to govern these sulfur contaminants level? If so, what is the specification number?

Thanks very much for any valuable input.

Yours truly,

Alex LEE
- Hong Kong, China

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Mr. Lee, I have heard apocryphal stories that before the industrial revolution and the widespread burning of coal, silver used to not tarnish. If a quasi-historian on silver can confirm or refute this, I'd appreciate it because I always wondered whether it was true or urban legend.

But the fact is that today silver tarnishes no matter where you live or where you use it. If you want silver to be tarnish free you have to coat it with something. In the case of the need for conductivity, there are commercially available organic topcoats designed for this purpose, or at higher cost the parts can get a flash of palladium or rhodium plating. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey