Metal finishing Q&As since 1989

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What can I plate over aluminum?

2005

What can I plate over aluminum, conducts electricity, has corrosion resistance for 50 yrs, and is cheap?

This is for an electronic box that need to press against other things and make electrical contact. We don't want the electrical contact to go bad after a while.

The box sits in a factory. 0 to 70C. There could be moisture in the air. No acid in the air.

Electroless nickel?

George Weinstein
- Cambridge, Massachusetts

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2005

1- Electroless nickel(EN). Yes (preferably high
phosphorous over 10-12% EN).
2- 50 years. Not very likely (20 perhaps), but we all may
be dead by then so what the heck.
3- Cheap. It depends. If you compare it against gold that
could last that long, it certainly is cheap.

Guillermo Marrufo
Monterrey, NL, Mexico

What about yellow chromate? How will that hold up over time?

George Weinstein
- Cambridge, Massachusetts
2005

Poor conductor. Limited corrosion resistance. Limited life.

Guillermo Marrufo
Monterrey, NL, Mexico
2005

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2005

Dear Mr. Marrufo,

1) Where can I get data on corrosion resistance and conductor resistance (ohms) for both chromate and the different kinds of nickel plating?

2) Ideally, a table showing several options in columns and in the rows: corrosion resistance, electrical conductor, approx. relative price. Where on the web would one possibly find that?

3) How is corrosion resistance quantatively specified?

4) How is condoctor resistance quantatatively specified?

5) Is there a place on the internet that shows relative price for a variety of options?

We are working in an extruded AL box.

George Weinstein
- Cambridge, Massachusetts