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topic 0434

Non-cyanide silver plating baths?

A discussion started in 1996 and continuing through 2014.
Add your Q. or A. to restore it to the "Current Topics" discussions.


RFQ: I am seeking vendors of non-cyanide silver plating baths. Any vendor is welcome to respond.

Joel Bandstra
- Johnstown, Pennsylvania
^- Sorry, this RFQ is outdated
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A. Dear Joel, Try Technic in Providence, Rhode Island USA, ask for Hrant Shoushanian, he developed a good process.

Good luck,

David Guleserian
- Rhode Island


Q. Hi, I am looking to deposit Silver onto silicon, using either electrochemical deposition or electroless deposition. If you have any info on baths for these processes, could you please let me know. Thanks, Aundrea

Aundrea Tavakkoly
- Santa Barbara, California

November 26, 2008

A. Hi, folks. EPI (Electrochemical Products Inc.) [a supporting advertiser] and Zinex, and possibly others, offer cyanide-free silver plating baths. Usually these have been restricted to electronics applications rather than decorative use as the color is a bit "off" -- but we may need to start accepting it even if the color is slightly different.


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

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(1998) -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

RFQ: I need information where I can buy a cyanide-free silver bath. I have heard that such a bath exist in USA but I need more information.

Best regards

Jorgen Pettersson
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A. Technic is one company that sells that product. They call it cyless silver. I think that they were the first major company to market a cyanide free silver.

James Watts
- Navarre, Florida


A. Ebrite 50/50 an alkaline non-cyanide silver is being marketed by EPI (Electrochemical Products Inc.) [a supporting advertiser]

bob morrison
- ormond beach, florida


A. Pyrophosphate silver bath:

potassium pyrophosphate.......100-350 gm
ammonium carbonate...........20-145 gm
silver pyrophosphate..........15-90 gm
water.........................1 lit
SS anode

Goran Budija
- Zagreb, Croatia

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Q. Hey, we have a small job shop in Israel. we make coatings of silver on copper-zinc alloys. we are working with silver 90, cyanide silver bath, and want to replace with non-cyanide bath. Really thank for any information from people working with such bath. problems? , change in equipment?, smell?, stability? etc. Thanks.

Ido Mashall
- Israel


A. You can try with potassium ferrocyanide silver plating bath:
40 gm silver chloride
200 gm potassium ferrocyanide 2
0 gm potassium carbonate
stainless steel anode
0,5 A/dm2-3V-20° C (temp.)

Goran Budija
- Zagreb, Croatia

May 21, 2009

A. Hi, Ido. There are commercial non-cyanide silver plating baths available from such suppliers as the website's supporting advertisers EPI (Electrochemical Products Inc.) [a supporting advertiser] and Zinex.

However, these have usually been reserved for electronic applications as even the vendors acknowledge that the color isn't quite right to match conventional cyanide silver plating. But things are always getting better and you can certainly try them. Good luck.


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

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Q. We use electroplating to silver plate copper and other metals. Is there a silver plating solution that does not contain Cyanide? If so please provide the contact information.

Jay Sandridge
- Amarillo, Texas USA
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A. Some cyanide free silver plating baths:

Ferrocyanide bath:
10 gms silver chloride
20 gms potassium ferrocyanide
20 gms potassium carbonate
1 lit water,SS anodes

Pyrophosphate bath:
15 gm silver(in nitrate or phosphate salt)
100 gm potassium pyrophosphate
25 gm ammonium carbonate
1 lit water

Ferrocyanide-sulphite bath:
add 40 gm sodium sulphite to previously described ferrocyanide bath

Goran Budija
- Zagreb, Croatia

March 23, 2011

Q. Are these solutions solderable? I'm looking for a PCB non cyanide silver solution


Mauricio Gott
- PUEBLA, Pue, Mexico

March 2011

A. Hi, Mauricio

As you probably know, there is much more to successful commercial electroplating than mixing together raw chemicals. It is typical to use proprietary chemistry rather than generic. Proprietary non-cyanide silver plating solutions are available from EPI (Electrochemical Products Inc.) [a supporting advertiser] and Zinex, and I'm quite sure that they will advise you that they are highly solderable. Good luck.


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

June 10, 2014

Q. I would like to silver plate small copper sheets. Those copper plates have mirror like surface. My silver plated copper should have a mirror like surface.
Do you have any experience with any of the following baths? Can you offer for me a working bath recipe to get good silver surface?
I found informations about succinimide, thiosulfate, 5,5-dimethyl hydantoin and about potassium iodide based baths. These bath recipes from patents from the internet.
For me succinimide based bath was the most promising. I bought the ingredients, but before the first try I found an article about stability problems. If I don't use the bath do I still have to maintain the bath pH regularly? How often? And if I won't, just before the next use? Something like this:
AgNO3 36 g
Succinimide 55 g
Potassium nitrite 42 g
Diethylenetriamine 2 ml
pH9,5 with Potassium hydroxide

5,5-dimethyl hydantoin is in the most recent patents but no information about how to maintain it. So how to maintain it?
Silver ions as silver 5,5-dimethyl hydantoin 40 g/L
5,5-dimethyl hydantoin 70 g/L
Sulfamic acid 35 g/L
Potassium hydroxide 50 g/L
Potassium nitrate 15 g/L
2,2-thiodiethanol 8 g/L
pH 9.5
Thiosulfate: poor adhesion... What does it mean poor adhesion?The silver will peal off from the copper?
Potassium iodide: Not much information about bright silver plating with this. Do you know how to make bright silver plating with this?
Silver Iodide 41 gm/liter (.175 mol/liter) Potassium Iodide 400 gm/liter (2.41 mol/liter) Calcium Formate 16 gm/liter (.123 mol/liter) Sodium Nitrate 40 gm/liter Gelatin-Purified 2 gm/liter Calfskin _

Maac Bakody
artist - Gyor, Hungary

June 11, 2014

A. Hello Maac,
The only person(s) that can answer your questions is someone who has experimented with a non-proprietary bath. The people that hold the patents will not reveal anything. I installed my first non-cyanide silver bath in New York City in 1992. At the time, I worked for a leading company that specialized in precious metals for electroplating, so I had plenty of technical support from headquarters. I think your best bet is to go with a proprietary bath so you can get the support and service you require.

Mark Baker
Process Engineer - Malone, New York USA

June 14, 2014

A. Try ferrocyanide bath; ferrocyanides are non toxic cyanide compounds and that type of bath is very stable and easy to prepare. According to old russian books, it can be used for bright plating too. Formula: 40 gms silver chloride, 200 gms potassium ferrocyanide, 20 gms potassium carbonate, 1 lit water, stainless steel anodes. Hope it helps and good luck!

Goran Budija
- zagreb,Croatia

June 15, 2014

!! But ferrocyanide with acids still can produce hydrogen cyanide, which is toxic. And you have strong acids around, because of the cleaning step.

Maac Bakody [returning]
artist - Gyor, Hungary

June 17, 2014

A. Yes, but there are no perfect solutions, even cyanide free plating solutions are more or less toxic. Ferrocyanide based technology is simple, safer than cyanide based, very stable, and results can be very good. You can try pyrophosphate based bath (see my previous answers, formula from old ex USSR books). You can buy proprietary bath too...

Goran Budija
- Zagreb,Croatia

Non-cyanide Silver Electroplating rubs off with a pencil eraser

November 10, 2014

Q. I help manage a non-cyanide silver electroplating process designed by Technic Inc. Our plating components appear to plate ok, but when we take a hard eraser to the surface of the component, we can rub off the silver to reveal copper underneath. We have been trying to experiment with the time in the plating tank and the amps delivered to the plating tank to try and increase the durability of the silver component. We clean the components in a heated alkaline cleaner solution as well as 10% sulfuric acid before rinsing them and plating the components.

We have been running this process for over a year, and the original components did not have this problem. Does anyone have any ideas that could identify the problem or improve our component durability?

Christopher DeSilva
- Chicago, Illinois, US

November 19, 2014

A. Hello Christopher,
If all the components in the bath are within operating parameters, I would ask Technic if it's time to carbon treat the bath. I have used a SOFT ERASER before to "polish" dull finishes, but never a hard eraser. As you know, silver is a soft metal and depending on your plating thickness, it may rub off. I would also verify the plating thickness to be sure you are getting what your requirements are. If this eraser test you perform is for adhesion testing, why not perform a bend test on Cu wire? If memory serves me correctly, there is a dilute sulfuric dip after the Ag plating process. Is the dip within operating parameters? A simple lab titration will verify this. Hope this helps!

Mark Baker
Process Engineer - Phoenix, Arizona USA

November 20, 2014

A. Seems your silver strike is too high in metal.

robert probert
Robert H Probert
Robert H Probert Technical Services
supporting advertiser
Garner, North Carolina

Editor's note: Mr. Probert is the author of Aluminum How-To / Aluminio El Como

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