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Blisters, streaks and smuts in Tin Plating on Aluminium

We are manufacturers of Electroplating Chemicals and we have to set up a new plant of TIN Plating on Aluminium. After cleaning Al we went for electroless Nickel and then Cu plating but it did not work.Formation of BUBBLES are seen particularly on the edge of Plate after Cu Plating. Can you suggest an alternative to this.

Shyam Kundekar
Suppliers of Electroplating Chemicals - Mumbai, Maharashtra, India
2007

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Hello, Shyam. You will need to research the topic of plating on aluminum further, but after cleaning and before electroless nickel or cyanide copper plating you need double zincating. It is important to advise the shop owner to retain a plating consultant.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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2007

Try to skip the copper step since is not obligatory.
When you plate tin ,start with low current density (below 1 amp/dm2).
If you'll still having blisters you must review you aluminum pre-treatment .
Good Luck.

Gabriel Schonwald
Bnei Berak, Israel

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The EN needs to be an alkaline strike quality for optimum adhesion. Plating over any EN has a built in problem. Very few people running a new line realize how fast nickel passivates and take their sweet time from the EN thru rinses and into the final plate tank. No surprise that you are having a problem.

James Watts
- Navarre, Florida
2007

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You don't specify if you are using a EN specifically formulated for plating on Al (generally an alkaline bath. Also what Al alloy or alloys are you plating over. Are the bubbles blisters or some other type of reaction? If the bubbles are blisters do they go only to the EN or are they bubbling (blistering) off the base metal?

Gene Packman
process supplier - Great Neck, New York
2007

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Sir,
improve cleaning cycle, ENP is first made by alkaline solution,then follow by regular ENP, use high efficiency copper plating bath if you are using cyanide copper bath .

Vijay Parmar
- Mumbai, Maharashtra, India
2007

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Mr. Shyam

Please note that you have to create a zincate bonding dip after cleaning before plating as clearly pointed out by Mr Ted.There are lot of propatatory process available in the market.

P. Gurumoorthi
electroplating process chemicals - Chennai, Tamilnadu, India
2007

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Mr.Shyam kindly take note of Mr.Ted who has rightly suggested you a double zincating method,that is strike a thin layer of electroless zinc then strip it once and then plate a thicker layer.also go by mr.gabriel and kindly skip the copper layer instead plate tin directly on electroless zinc and make sure your tin bath is on while loading the components to avoid stripping of zinc layer in tin solution

S.Mohan Kumar
- Bangalore, Karnataka, India
April 15, 2008