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Electroless nickel on very thin aluminium

 

I am looking for ideas as to how to electroless nickel plate very thin films ( less than a micron) on aluminium. Conventional wisdom is to use a zincate pretreatment, but even the proprietary dilute processes are too corrosive, and zinc is undesirable for electronic reasons any way. In the early days of electroless nickel there were all sorts of ideas of special direct nickel plating of aluminium. Does any one have any favorite recipes please?

John Sherborne
- Sunbury, London, UK

I can't address your Zincate corrosion problem, but, if you get beyond that, try an electroless nickel strike in an older separate bath prior to entering the final bath. It is my understanding that the zincate dissolves prior to the nickel depositing. This leaves the contamination from the zincate in the older bath and makes the good bath last a lot longer.

Pete Faxon
- Oxnard, California

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Mr. Sherborne:

You might want to talk to the people in the brush (selective) plating field. They have special nickel solutions and preparatory steps to aviod the zincate yet providing good adhesion. They might have somsthing for your problem.

Guillermo Marrufo
Monterrey, NL, Mexico