Metal finishing Q&As since 1989

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Coating Aluminum onto Copper

I am a material sales Engineer. Could anybody Please share their expertise how to coat good quality 2 micron Aluminum layer on copper? Thanks,

Michael Wu
sales - Toronto, Canada
February 19, 2010

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Hi, Michael. It will go quicker if you explain your situation and what you are trying to achieve. Aluminum is not electroplateable from conventional aqueous baths. You would need to have it done from a proprietary organic bath (only one shop in No. America), or vapor deposited. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 19, 2010

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Aluminum can be coated on copper by plasma PVD processes.

H.R. Prabhakara - Consultant
Bangalore Plasmatek - Bangalore Karnataka India
February 22, 2010

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February 24, 2010

Thank you very much Mr. Mooney and Prabhakara.
Sorry for the later reply. This is the first time I am using this system. I was waiting for email inform.
I am looking for somebody that can coat 2 micros pure aluminum onto both side of electrical copper parts. The coated area is about 18 square cm each end.

Mr Mooney,
1. Could you please tell me what is the quality difference for organic plating and PVD ? For each coating method, which field can apply better?
2. Can those quality be substituted? Which standard can organic plating and PVD achieve?
3. what is the coating cost difference?
4. Can you suggest me the shop that can do organic coating and few shops can do PVD in N.America?

Mr. Prabhakara,
1. What kind of PVD do you suggest for good quality at low temperature that will not damage the parts.
2. Is the coating easy controllable to achieve 2 micro even thickness of pure aluminum?
3. How is the quality? Which standard can PVD achieve?

Thank you very much in advance.

Michael Wu
- Toronto, Ontario, Canada

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February 28, 2010

Dear Mr.Wu,
1.One can use either magnetron sputtering or cathodic arc techniques. Sputtering gives a smooth coating while the arc process results in a slightly rough surface. Generally adhesion, deposition rate as well as film density are better in the arc method though latest sputtering techniques are also good in these aspects. I am a bit biased as I use cathodic arc for depositing various films including copper.

2. Coating thickness is well controllable to 2 microns. But uniformity of thickness depends on the geometry of the substrates, substrate manipulation etc.

3. Generally user specifies the requirement. I am not aware of any standards. Quality is known to be better than electroplating.

H.R. Prabhakara - Consultant
Bangalore Plasmatek - Bangalore Karnataka India

Have you considered electroplated silver. At that thickness, it is probably cheaper than the high tech aluminum processes.

James Watts
- Navarre, Florida
March 1, 2010

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First of two simultaneous responses -- March 2, 2010

Dear Mr. Prabhakara,

Thank you for your help.

Could you please let know what the coating cost difference between organic plating and magnetron sputtering , cathodic arc techniques?

What is the lowest substrate temperature for magnetron sputtering and cathodic arc techniques?

How long the parts have to be in the temperature?

I'd like to know if the heat will affect the parts.

Thanks.

Michael Wu
- Toronto, Ontario, Cananda

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Second of two simultaneous responses --

The only company that does the pure aluminum electroplating in an organic bath is out of Minnesota. You should be able to find them on a web search. On the other hand, lots of people do IVD aluminum, so you can do a web search for IVD aluminum. It will work well if your part doesn't have any deep I.D. holes to cover.

Jon Barrows, MSF, EHSSC
GOAD Company

Independence, Missouri

March 3, 2010

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First of two simultaneous responses --

The smoothest, densest films are deposited by sputtering or the electroplating process (which only one company does). I'm not sure about the temperature in the electroplating process, but you should be able to keep the temperature low while sputter depositing aluminum. A company that I work with sputter deposits aluminum on the inside of landing gears at low temperatures.

In the IVD process, the aluminum is thermally evaporated, and the coatings have a very open structure. I would not recommend cathodic arc -- the arc produces molten droplets of metal -- macroparticles -- that can stick on the surface. This is not much of a problem for high melting point metals (titanium, chromium), but is bad for aluminum. Also hard to keep the heat down when depositing by cathodic arc.

Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
March 3, 2010

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Second of two simultaneous responses --

Dear Mr.Wu,
These are batch processes. Cost depends on the quantity among other factors. Coating temperature could be anywhere from 100 to 400 °C depending on the machine, the substrates, etc. Duration also depends on coating thickness, geometry, operating parameters of the machine etc. Unless one studies the parts to be coated in detail it is not possible to comment on temperature affects !

H.R. Prabhakara - Consultant
Bangalore Plasmatek - Bangalore Karnataka India
March 3, 2010

Thanks James for your suggestion. My customer said the film has to be Al.

Michael Wu
- Toronto, Ontario and Canada
April 12, 2010

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April 12, 2010

Dear Mr. Prabhakara,

Thank you very much for your help.
For the big quantity production scale, how much do you think the price range for the quality 2 micro Al coating is?

Thanks,

Michael Wu
- Toronto, Ontario and Canada

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Dear Mr.Wu,
I am not sure if it is proper to answer your specific question in this forum. However I would try.I have a coating chamber of size 1000 x 1000 x 600 mm. The running cost per cycle is about Rs 15,000/- for aluminum. The number of components that can be coated per batch depends on the geometry and other details of the job.

H.R. Prabhakara - Consultant
Bangalore Plasmatek - Bangalore Karnataka India
April 12, 2010

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Hi. I see nothing anti-competitive or wrong, H.R., with giving people a general feel for the cost of processes that they are not familiar with. People wanting to make a salad need to know that artichokes are more costly than lettuce; people wanting to make counterweights need to know that lead is less costly than gold, and people wanting aluminum coatings need to know that magnetron sputtering is more or less costly than other alternatives -- so thanks. The problem would come in more exact pricing in a way that could lead to suppliers toward colluding to hold a price high. So we thank you for offering Michael a rough idea of the cost, and let's leave it at that :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 13, 2010