Silver Tarnishing Question

Questions on polishing, restoration, conservation + manufacturing techniques
DougalDog
Posts: 5
Joined: Sat May 30, 2015 4:47 am
Location: England, Lincolnshire

Silver Tarnishing Question

Postby DougalDog » Tue Feb 26, 2019 7:06 am

Hi,
This may seem like an odd question.
I have about 50 pieces of silver, with the odd plated item, all in a cabinet. The silver is English, Russian, Japanese, French, Indian, Italian, American, German and Austrian. I only clean it once or twice a year, as it generally seems to stay tarnish free, apart from one piece.
This one piece is the only American sterling silver item I have, and it tarnishes much quicker than any of the other items, why is this. Does anyone know how this can be, am sure there is a simple explanation. I do not mind cleaning it more often, just curious as to why it tarnishes sooner.
Thanks,
Dave

silverligther
Posts: 17
Joined: Thu Dec 22, 2016 6:41 am

Re: Silver Tarnishing Question

Postby silverligther » Sat Feb 08, 2020 1:37 pm

DougalDog wrote:Hi,
This may seem like an odd question.
I have about 50 pieces of silver, with the odd plated item, all in a cabinet. The silver is English, Russian, Japanese, French, Indian, Italian, American, German and Austrian. I only clean it once or twice a year, as it generally seems to stay tarnish free, apart from one piece.
This one piece is the only American sterling silver item I have, and it tarnishes much quicker than any of the other items, why is this. Does anyone know how this can be, am sure there is a simple explanation. I do not mind cleaning it more often, just curious as to why it tarnishes sooner.
Thanks,
Dave

Hello Dave,
I have the same problem with a silver tray from Italy. It is 800|1ooo and made by the first registered silversmith in the City of Bergamo. It tarnishes within one week. I hope that somebody with metallurgy knowledge will find your post and explain the background.
Josef

AG2012
contributor
Posts: 3719
Joined: Fri Apr 13, 2012 9:47 am

Re: Silver Tarnishing Question

Postby AG2012 » Sat Feb 08, 2020 4:28 pm

Hi,
Tarnish is actually silver sulfide, chemical compound of silver and sulfur from the air.
If there is difference in tarnish under the same conditions,it depends on other components in the aloy.
Regards

amena
contributor
Posts: 810
Joined: Fri Jan 20, 2012 8:42 am

Re: Silver Tarnishing Question

Postby amena » Mon Feb 10, 2020 11:19 am

From the thesis of Francesco Sponza
RESISTANCE TO TARNISHING OF SILVER ALLOYS
http://tesi.cab.unipd.it/40143/1/Tesi_F ... 416-IR.pdf
The microstructure of the alloy is another element that can affect tarnishing resistance,
 Furthermore, a material with a fine grain and homogeneous composition has greater stability and resistance to corrosion phenomena. In general, the presence of impurities or inclusions can increase sensitivity to the phenomenon of tarnishing favoring the starting of the reaction.
In the same way, surface roughness is a source of greater tendency to blackening, as it increases both the exposed surface and the surface energy.
A metallurgical factor of some importance is porosity: in addition to increasing the surface and the energy of the same, it can create points where an accumulation of aggressive substances can occur, which accelerate the corrosive process (pitting corrosion).
As regards the state of the material (casting raw, work hardened, annealed), better stability conditions of the material can be achieved by minimizing surface reactivity, a condition that can be achieved by eliminating by heat treatment everything that can cause situations of stress or tension (strain hardening, etc.).


Sorry for a little broken English


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