Sciencemadness Discussion Board

tarnish free silver chromium alloy

xxxxx - 2-8-2012 at 04:45

i was interested in whether the addition of a few percent of chromium could stop silver from tarnihing in the same way chromium copper (2% chromium) does not oxidize by passivating the oxide coating on the surface of the copper.
even though silver reacts with sulfer compounds in the air instead of oxygen i thought the two reactions might be similar enough for this to work. could some tell me if this would work and why or why not.

hyfalcon - 2-8-2012 at 19:14

That's why many silver necklaces have a palladium coating electroplated onto them.

elementcollector1 - 2-8-2012 at 20:00

I thought it was rhodium?

Fleaker - 5-8-2012 at 07:27

It can be either, but typically rhodium.

hyfalcon - 5-8-2012 at 10:54

Sorry, right family wrong element. What he said.:D

Poppy - 12-8-2012 at 18:50

Quote: Originally posted by hyfalcon  
That's why many silver necklaces have a palladium coating electroplated onto them.


Hilarious, hahahaaha
Then why are they made of silver at all?

elementcollector1 - 12-8-2012 at 21:48

I believe it was that sterling silver tarnishes eventually due to the sulfur compounds in the air, and the rhodium is plated over to prevent this. Although that does raise the question - why bother using sterling? You can't even see it.

Makes rhodium easy for element collectors, though.

buzzoff - 22-8-2012 at 17:53

Seems to me, that it is the copper content of Sterling Silver that increases its vulnerability to tarnishing. Fine Silver (AKA Pure Silver) resists tarnishing a lot better.