Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Electroless Nickel Plating on Gold?
December 2, 2008
Hello!
Is it possible to plate Nickel electroless on a Gold surface out of and Phosphorus based solution with a suitable pretreatment? Important would be to get an ohmic contact between those layers.
Thanks a lot! Andreas
student - Stockholm, Sweden
December 2, 2008
Hi, Andreas. I think it is as easy as applying electroplating current to the component for a second. As soon as deposition starts, the autocatalytic plating should continue.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Ted's answer is good, but for most of us it will take a few seconds, like 5 - 10.
James Watts- Navarre, Florida
December 3, 2008
December 4, 2008
The electrons take it a little easier and run a little slower down south than up in cold Sweden.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 8, 2008
Dear Ted and James!
Thank you very much for your answers! Unfortunately, I have no possibility to contact the seed layer electrically. So I am not able to force some cold Swedish electrons into the gold layer :-)
Is there any other possibility to start the autocatalytic reaction? I read about striking solutions (H20 + HCl + NiCl / PdCl / SnCl), but I am not sure if they will work for gold.
Best regards, Andreas
- Sweden
December 9, 2008
In the old days, if we had a group of parts that were tough to get started to plate. we would touch one of the parts with a cadmium ball that we had on a piece of all thread. It would start plating in a mater of seconds.
Another cheat is to use an alkaline rinse with the pH modified with ammonium hydroxide and go into the EN tank with the trace of the lower pH on the surface. It can jump start some metals and will definitely accelerate the start of common metals EN plating.
OK, why can you not use electricity to kick off the plating. I can not think of any reason that it would be IMPOSSIBLE.
- Navarre, Florida
December 11, 2008
Hello James!
Thank you very much for your hints! Can you provide some further informations of that alkaline rinse? I am not really a chemist: Did I got that right, that a pH-gradient may induce the electroless plating? Our plating solution has a pH value around 4.35.
I am working on a selective deposition of Nickel in microscale polymer molds. The seed layer beneath is not a plain surface but also structured in microscale. These spots cannot be connected to each other!
Best regards, Andreas
- Sweden
Hello again!
I tried now to plate Ni electroless on a Au-seed layer. Unfortunately I had no success with the suggested pre-rinse in ammonia
⇦this on
eBay or
Amazon [affil links] solution. I was also afraid, that the pH-value of the solution (around 4) will be increased by placing a sample coated with ammonia solution in it.
My second approach was a bit more successful: I blended a striking solution out of DI water, HCl and PdCl. I exposed the sample for 2 mins in this solution and gently rinsed it in DI water afterwards. The plating started immediately but rather uncontrolled.
I try now to understand the chemistry behind this striking process. What happens with the PdCl on the Au surface? How strong is the bond to it? I would be very glad about any hints!
Thanks a lot in advance!
Best regards, Andreas
- Sweden
February 10, 2009
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