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Direct nickel/gold plating of aluminium/brass electronic contacts

June 9, 2011

Hi:

I have an integrated chip that has 28 pins as connectors. The chip is old, discontinued and thus rare. The pins develop grey/black coating (tarnish?) in a month of scratch cleaning them.

I am not sure about the material. It is non-magnetic, most probably aluminium or brass. I want to have plating to stop this tarnish cleaning routine. The plating must be highly conducive as the chip operates at low voltages. Because all the leads are independent thus each lead has to be plated individually (also to avoid short circuiting the chip) and also because the main body of chip is made of plastic I cannot risk immersion.

I googled and found there are plating pens available for such fine jobs. Thus here are the questions.

Using the plating pen, can I directly nickel or gold plate the pins?

What will happen if I skip nickel plating before gold plating, gold will come off after a while? or plating will not happen altogether?

What if I try direct nickel plating without zinc plating first, nickel will come off after a while? or plating will not happen altogether?

The main goal is to prevent tarnish to have good but hard conducting surface all the time. I don't care about looks.

Regards

Haroon Chaudrey
DIY electronics - Ellicott City, Maryland

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Hi Haroon

I have never come across DIL frames in either brass or aluminium. Both are unsuitable for various reasons.

I would strongly advise against trying to electroplate anything onto a chip assembly. There are always stray voltages that could easily destroy the circuit. (That's why you earth everything before handling)

The simple solution would appear to be dip soldering. You can afford to use a fairly aggressive flux. Be sure to clean off all flux residues when you have finished. Any alcohol should do the job or it is quite safe to use water/detergent (rinse well and dry before storing)

Geoff Smith
Hampshire, England
June 12, 2011

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June 14, 2011

Hi Geoff:

Thanks for the response. Yes! I can tin the leads with solder but no permanent soldering.

I do have some chips (lower standard) to waste in experiments of electroplating or electroless plating and not worried about static electricity. In fact, I found them very tough as I cleaned one experimental chip with wire bush using Dremel [on eBay or Amazon] few times and it still works.

Thus, the questions remain considering I am unsure about base material.

What will happen if I skip nickel plating before gold plating, gold will come off after a while or plating will not happen altogether?

What if I try direct nickel plating without zinc plating first, nickel will come off after a while or plating will not happen altogether?

What if I try direct silver plating and then gold plating? Plating will come off after a while or plating will not happen altogether?

Haroon Chaudrey
- Ellicott City, Maryland, USA