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Silver Nitride Discoloration Problems

2003

I have a shotgun with a "silver nitride" finish. This is supposed to provide superior corrosion resistance. However, the metal on the receiver of this firearm has become discolored...twice. I sent the piece back to the manufacturer to have it refinished, which they did. Two years it is discolored and stained again. This firearm has never even seen rain.

Only two gun oils have ever been used on this piece, Browning gun oil and Remington gun oil with Teflon.

The factory says to send it back again, However I would like to understand the heat treating process that is involved with applying the finish. The receiver should not be taken up and down in temperature for fear of ruining the hardness and other properties. So, to apply a Silver Nitride finish does the steel see elevated temperatures during application? I am a materials engineer so the details are welcome although finishes are not my forte'.

Thanks for any insight.

James A. Gill
- Kennett Square, Pennsylvania

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2003

I have been inquiring about this same question. Did you get an answer? Browning just states it resists corrosion but keep it oiled. My skin is very acidic and causes fingerprint very rapidly how is your browning holding up? I am looking at the XS skeet . Thanks for any feedback

James,

Did you get a reply from Browning as to the silver nitride durability?

Thanks,

Gary Miller
- Vienna, West Virginia

The finish on your gun is not silver nitride. Silver nitride, formula Ag₃N is a highly unstable silver compound formed by the condensation of the silver amine complex at high pH. Silver nitride is so sensitive that simply touching it is sufficient to cause it to decompose violently.

I unfortunately cannot comment on what the finish is on your gun, but be assured that it is not silver nitride.

Best regards,

James Edward Hoffmann
- Houston, Texas
2003

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2003

Very curious situation. I tend to agree with Mr. Hoffman, so I decided to try to track down this 'silver nitride finish' and investigate the possible typo or misunderstanding. Only to find that virtually every gun manufacturer offers this 'silver nitride finish'!

Maybe one of our vacuum deposition experts will have something to say about what it actually is?

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

I wonder to know the crystal structure of Ag3N. Anyone know?

Hailin Yu
- Changshu, Jiangsu, China
November 10, 2008

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I know this thread is a little old but I'll jump just in case anyone is still watching.

The finish on your Browning is not Silver Nitriding, regardless of what Browning says. It IS a nitriding process but much more like Ion Nitriding.

This is a heat-treating process done in an atmospherically controlled furnace. The resulting finish is very similar to the case-hardening/case-colored finish you see on older side by sides. Being controlled, the oxidized colors do not show.

When the receiver is removed from the oven, there is a brown scale on the metal that must be polished off. Because this new hardness is very thin, it's possible to actually polish through the hardness into the softer material below without knowing you did so.

The softer material is what eventually shows the "tarnish".

Doug Braker
- Backus, Minnesota, USA
April 29, 2010