No registration or passwords; no pop-up ads -- just aloha, fun, & answers.
(as an eBay Partner & Amazon Affiliate earns from qualifying purchases).
Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Advertise
 
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub  Where the
world gathers for metal finishing
Q&As since 1989



-----

How to Silver Plate Aluminum




Q. Good morning everyone,
We are currently doing the Silver plating process on Electrical part,
Our current process is-
1 Caustic dip
2 Nitric-sulfuric-Gictane 70 dip
3 Nitric Acid dip
4 Zincate 1
5 Nitric acid 2
6 Zincate 2
7 Copper strike
8 Copper plate
9 Silver strike
10 Silver plate
After silver plating part is visually okay, but after oven for 30 mins we get minor bubbles in line inside the ID step.
Please recommend the solution regarding this issue.

Prasad Patwardhan
- Pune, Maharashtra
May 11, 2021




⇩ Closely related postings, oldest first ⇩



Q. I WOULD LIKE TO PLATE ALUMINIUM WITH SILVER. I HAVE USED THE GLASS SILVERING PROCESS BUT THE RESULTS ARE NOT VERY ENCOURAGING. CAN SOMEONE SUGGEST AN ALTERNATIVE DIRECT PLATING PROCESS.

M. Khawar
Islamabad, Pakistan
1997


"The Surface Treatment & Finishing of Aluminium and Its Alloys"
by Wernick, Pinner & Sheasby

on AbeBooks

or eBay or

Amazon

(affil links)

A. Hi M. Two-part silvering isn't the best way to plate onto aluminum. There are two possible methods: phosphoric acid anodizing followed by plating, or, more conventionally, zincating (or proprietary zincate alternatives like Alstan or Bondal) followed by plating.

Briefly--and you'd need to consult a handbook for more detail--you clean, etch, and desmut the aluminum, zincate it, strip in nitric acid, re-zincate, and alkaline copper plate. Then you may need a barrier layer of nickel, then you silver plate. Obviously, there are alternatives here and there, but it is quite a bit more complex than simply dipping the aluminum into a silvering solution.

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




Q. I'm going to open a silver plating shop (I have experience in nickel, copper, and gold plating). Could you answer the following questions please:
1.Does silver plate on the steel, nickel, aluminum or gold?
2.How about diffusion between silver and copper, is it necessary to have a barrier between them?

Thank you,

David Imeda
- Ottawa, Canada
2002


A. Aluminum cannot be plated directly; it will require zincating followed by copper or electroless nickel plating. The other materials can be silver plated but all except gold are less noble than silver, so silver may "immersion plate" on them. You may need to employ a silver strike and/or a 'hot lead' for silver plating.

Whether diffusion will be an issue depends upon the application. If the plating is decorative rather than functional, and the temperature the item sees ion service are moderate, a barrier layer of nickel between the copper and silver may not be necessary.

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


A. At our company we plate various gold and copper alloys with a silver strike then an antique silver plate. The plating is on jewelry, so it is purely decorative. Since I have been here we have never had any problems with diffusion. At least, it has never caused customer returns that I am aware of.

Courtlan Erickson
- Salt Lake City, Utah, USA




Q. We have to silver plate an aluminum tube, alloy 6063T6. Diameter of the tube is from 4" to 10" . Thickness should be 7 microns (micro-meters) and the surface should be as smooth as possible. There will be high frequency currents and we have to improve the conductivity. I would like to know how the process is and where we have to buy the chemical components to make the plating in Cordoba.

Thank you,

Ricardo de Goycoechea
- Cordoba, Argentina
2002


A. The first thing I would do is to vacuum deposit a few microns of pure aluminium over the formed material. This can be done with a simple vacuum deposition device. You can make your own for under $1000 and the rate of the device is near 1/minute. This is very common in the lighting industry.

John Powell
- Largo, Florida




Q. Hi,

I am trying to electroplate Silver over alumina substrate and I need to plate like 4 microns and fill the pores of alumina. Can you tell me whether the number of electrons released by Silver solution at the anode is 1 or 2. What solutions do we use generally for silver plating.

Phaneendra Medida
Drexel University - Phili, Pennsylvania, USA
2002




Q. Respected sir,

I am working with cyanide silver plating bath. The main problem with this system is that there is a drop of 50% current after 10 min of plating ( cathode current density at 1 amp/sq.dm ). Please suggest me some method to overcome the above problems. Is it possible to add any conducting salt/additive to maintain the current of plating bath ?

Ashok nalawade
- India
2003



Ashok,

You have low free cyanide concentration in your silver solution.

Regards,

Anders Sundman
Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden





Silver plating over aluminum for PIM (Passive Intermodulation) avoidance

Q. I'm looking for a silver plating over aluminum process to be used in radio frequency applications, does anyone knows about which is the correct process to avoid Passive Intermodulation (PIM)? any hints?

Regards,

Matias d [last name deleted for privacy by Editor]
electronic mfgr - Miami, Florida, USA
2004


A. Hi,

First of all, do you want to inhibit PIM in junctions (connections, etc.) or just in the device itself? The silver plating for the reduction of PIM in metallic walls of RF devices is DC standard electroplating. For the case of connectors, etc., the process used can be the same or maybe it is even better to use a softer metal. Anyway, silver always shows very good PIM response.

Regards,

Carlos Vicente
- Darmstadt, Germany




Problems silver plating aluminum castings

Q. We use silver plated castings in electrical circuits where silver plating is necessary for making good contact.

We perform silver plating on Aluminum castings. We find that a large percentage of castings have problems of micro-porosity opening up after first cleaning (pickling) using mixture of HF and HNO3 acid. Can someone advise me how to avoid such porosity.

Plating on such microporosity causes the plating to get damaged (maybe due to entrapped acid/ chemicals) which in turn increases contact resistance.

Gunvantray Patel
- Vadodara, India
2004




Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)



Silver plating on 2024 aluminum

Q. Dear sir,
I want to silver plate the components on aluminum 2024 alloy material; the components are for aerospace application, and thickness of base material is about 2~3mm. Actually I want to plate silver and whatever the starting process it will not matter. It may be copper or any other suitable process. So please tell me the procedure how I can start this process. We have more then 10 years experience plating, with personnel involved in cadmium and zinc plating on ferrous alloys and anodizing, Alodining also on aluminium parts. So please tell me any suitable process to plate silver on these parts.

Mahboob Alam
AERO - Islamabad, Pakistan
2005


A. The most direct process would seem to me to be to zincate the aluminum after giving it a pretreatment similar to what you use when Alodining, strike it with a copper cyanide, cyanide copper plate it, cyanide silver strike, and cyanide silver plate. This sequence uses cyanide in all five processes, but at least there's no going back and forth between acid and cyanide processes, and I don't think there's anything "iffy" in it. It may be possible to skip the copper plate and/or the silver strike, but that would require some testing to verify.

You may need approvals and mil specs for aerospace applications though.

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


A. Mahboob,

Ted is right, cyanide plating lines are very easy to maintain, consistent and work relatively well when used in conjunction with a zincate or double zincate prior to your copper strike. But there are also Nickel strike and electroless Nickel baths that can be used successfully, if a good process is put in place. Start with your chemical suppliers. They should be more than happy to provide you with all the technical support you will need to find the process that best suits your needs.
Good Luck,

Michael Null
Plater - Methuen, Massachusetts, U.S.A.




Q. I have many gold plated chains that I would like to silver plated all at once. Is there is such a product to buy?
Also, Can you silver plate items with this composition is an alloy of zinc, nickel, and iron)?

Roger L [last name deleted for privacy by Editor]
jewelry - Penbroke, Nebraska, USA
2006




Silver plating an aluminum heatsink?

Q. Hi, I'm a university student and I study electronics to become an engineer. In my spare time, I mod computers. I also study electronics and electronic parts cooling issues for pleasure.

I need help to electroplate a thick layer of silver on a big heatsink made of mostly aluminum and copper. It has some tight bends and a complex shape and I'm not sure how to go with the "silvering".
I wanna do this for 2 purposes: 1. better contact between fins and unsoldered parts 2. a nicer look, but not necessarily mirror-finish. Just a nice silver coat.

I have studied electroplating and found out I need some chemicals like AgNO3 for my solution, which I can easily obtain. I would be grateful to know what concentration I need, what voltage I should use, how much time I should allow the reaction to take place, in what configuration should I place the silver elements that will be consumed and what additives/acids should the solution contain. Or any helpful advice.

41989

Thanks in advance,

Nemes Calin
student - Baia Mare, MM, Romania
2006


A. Try to find good plating shop--most of silver plating solutions are cyanide based.If you want you can use do it yourself cyanide free solutions.
Ferrocyanide based plating solution:
40 gm silver chloride
200 gm potassium ferrocyanide [affil links]
20 gm potassium carbonate
1 lit water, stainless steel anodes
Dissolve ferrocyanide in boiling water, add carbonate and then add chloride(fresh, you can make it by mixing AgNO3 solution with kitchen salt solution),boil 30-180 minutes, then filter it when cold, then you may use it!
Never try to mix it with strong acids!
Phosphate based solution:
25 gm silver nitrate (or better, pyrophosphate)
100 gm potassium pyrophosphate
25 gm ammonium carbonate
1 lit water
Stainless steel anodes
Aluminium must be zincated!Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia




Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)



Q. I have see in many cities in Asia, street vendors who will silver plate coins using an acid in a fish tank and a car battery! can anybody explain the process to me/ I would like to do a similar thing!

Len Horwood
Artist - Sydney, NSW, Australia
2007


A. Street vending of plating services would likely be illegal in the USA -- I don't know about Australia -- because it would not comply with the requirements for discharge permits. The scientific principles of electroplating, including examples for students, are addressed in our FAQ about How Plating Works.

Are you sure it's silver, not just something shiny? Decorative silver electroplating can only be successfully applied from cyanide-based plating baths. But it is possible to do a thin immersion plating of silver onto copper objects from relatively safe solutions. See our FAQ about Silver Plating at Home. Good luck.

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




How to do antimicrobial silver plating on aluminum?

Q. Is there a way to apply an anti-microbial silver plating over 6061AL? Can this be applied over Type II (Anodize) or Type III (Hardcoat) already in place?

Kevin Klocek
product designer - Norristown, Pennsylvania
June 23, 2008


A. Anodizing is a very good electrical insulator which makes it impossible to directly electroplate Type II anodized aluminum, Kevin. Is it possible to electroless nickel plate the aluminum instead of anodizing it? This is probably a more typical and direct route towards eventual silver plating.

Regards,

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


A. Ted,
The anodizing process vendor out near Reno, NV has a process where they silver treat anodizing to make it conductive. My guess is that it is a bit like the two step anodizing process which electroplates cobalt or another metal into the anodize for color.
If I remember correctly, one of the anodizing greats, possibly Charlie Grubbs, mentioned a similar process a couple of years ago.
Now, if that is enough to make it anti microbial is a good question.

James Watts
- Navarre, Florida




Multiple threads were merged: please forgive repetition, chronology errors, or disrespect towards other postings [they weren't on the same page] :-)



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

Q. I need to understand the complete process of silver plating onto aluminum. secondly, it is durable in usage? Thanks,

Daljit Singh
purchasing agent - India
August 10, 2010



simultaneous replies

A. To understand a complete process, you'll need to get and read a couple of books.
Durable is an extremely nebulous term. Its meanings are as many as people that try to define it.
The zincate step is the hardest to do well as there are only a few very poor visual indications of a good coat. The silver strike is very important and critical. Do you plan to use a nickel undercoat? If so look at alkaline electroless nickel.
The silver step is probably the easiest one.

James Watts
- Navarre, Florida


A. Daljit,

You need to give us some more details as to what you are expecting out of the coating rather than an abstract question. Please describe how the parts are to be used, what environment and what you would like the coating to do for you. That way someone may be able to advise you accordingly.

Brian Terry
Aerospace - Yeovil, Somerset, UK




Q. We produce a medical device whose components are either Type II or Type III Anodized. These are devices that are being constantly touched. Is there a method for doing a Copper Anodized surface, or would plating be a better, or more cost effective option? The main purpose is for Copper's antimicrobial properties to help prevent infections.

Thanks!

Steve Moulden
- Phoenixville, Pennsylvania, USA
August 9, 2013


A. Hi Steve. Thanks for bringing this one up. Antimicrobial finishes seem to be the next big thing. We received a press release from Macdermid on the subject this week, and I'm sure they'd be happy to try to answer your question as it relates to their potential solutions. Other major vendors are no doubt also intensely involved with the subject.

I doubt that anodizing and dyeing with a copper-colored dye would do much, and that you would need to plate the aluminum to achieve anti-microbial properties.

Regards,

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


help wanted ad
Production Manager for Plating Co. - AST, Arvada, CO
Junior Sales Representative - Resintech, Camden, NJ
Nadcap Chemical Processing Auditor - PRI, traveling



(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"