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topic 47136

Anti-Tarnish on Silver - chromate


2007

My name is Deepak Whorra,a fourth generation Silversmith.
The demand for Sterling Silver is reducing very very rapidly, primarily due to tarnishing issues and people having no time or inclination to polish off the tarnish. So I am doing research on what system/method to use to prevent tarnish:

1) E.Lacquer: Good protection but can reduce gloss, needs a well modulated and controlled plant with almost continuous operation, is quite expensive per square foot,etc.And not recommended for food containers. Also yellowing after some time.
2)Proprietary anti-tarnish dips - Per sq foot cost is reasonable though not low.But life of protection is very much less especially in Delhi's polluted ambient air.
3)Chromate based Dip coating : Cheap but protection life is poor.
4) Electroplating of chromate based chemicals like Tarniban,etc.: Decent life span and economical though not suitable for food containers. Effluent treatment can be problematic though.
My questions :
a) Why is everyone constantly telling me not to use Chromate passivation even for decorative products?

b) A second, maybe stupid , question- In India Teflon coating is aplied to cars and they do not change the colour but I am very happy in applying this to my cars. Is this possible on silverware without affecting the gloss or colour and will it protect against sulfide ?

c) A third question : Is there any progress on initial research done by Marc de Bonte on coatings of Silver-Germanium alloys ?

d) Any other solution ?

I know that this problem would have been posted many times but I do wish some answers to this in view of new technologies over the past few years including nano technologies

deepak whorra Deepak Whorra
     silver craftwork
New Delhi, India


2007

Hi, Deepak. The answer to "a" is that chromate is considered by some governments to be carcinogenic and its use is severely restricted by RoHS and similar standards.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey


2007

Hi Ted,

Thanks for answering one of my questions... Do you think that that CR6 usage is dangerous ?

What about nano technology coatings or Silver-Germanium alloy coatings ? Any further developments on that ? I am very keen to know because these maybe the only long term solutions for the moment

Deepak Whorra Deepak Whorra
     silver craftwork
New Delhi, India

3M Silver Protector Strips

2007

In this context -- for use on a food container -- yes, I think chromate is dangerous. Although I've mentioned some articles about tarnish prevention from time to time, sorry but I can't tell you the ideal approach for your situation or provide more insight into your propositions.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey


2007

Try Argentium(R) sterling silver-according to producer that silver alloy(925 parts silver/rest copper and some germanium)is very resistant to tarnish( and more expensive than ordinary sterling silver). Hope it helps and good luck!

Goran Budija
- Zagreb, Croatia


July 18, 2009

Can we plate an alloy of silver/Copper/Germanium ?

Deepak Whorra Deepak Whorra
     silver craftwork
New Delhi, India



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