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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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How to remove nickel oxide from a nickel surface
Q. I have a pure nickel surface with a very thin NiP-coating on it. I corroded it by hanging it for one hour in HNO3 vapour. Since I would like to see (with SEM) how the surface is corroded , I need to remove the corrosion products which are all over the place. But it must be done in such a way that it only effects the corrosion products and not the underlying layer. What kind of reagents or procedures are required for this?
Thanks in advance,
researcher R&D - Venlo, Limburg, Netherlands
2004
A. An interesting problem. Firstly, using an SEM will usually give you a beam penetration of a couple of microns, so you are not looking at the true surface of the nickel. This can be overcome by using specialised SEM surface analysis techniques. Secondly, how thick is the nickel oxide? If it is only a very thin layer, you may want to sputter clean it in a vacuum chamber, or you could polish it with a very fine 0.5 µm (or less) diamond paste. It all depends on what you call the surface....If you are not too concerned about the "surface" you could use a mild acid cleaner, possibly with anodic polarisation; I would avoid cleaners that contain hydrochloric acid, as chloride ions are really quite aggressive towards nickel.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004
You could try a forward polarity electrolytic treatment in a weak (5%) sulfuric acid solution. This will produce hydrogen that will act to reduce oxides and at the same time has little effect on nickel. I am not sure, but you may also want to try an immersion in ammonia. I know it is a very good solvent for many metal salts such as nickel sulphate and it could be just as good for nickel nitrate which is likely to be present in your "oxidized" nickel surface.
Guillermo MarrufoMonterrey, NL, Mexico
2004
Diamond turned mirror
Q. I have a related question. I have a diamond turned mirror that is an aluminum substrate with electroless Ni plating. It oxidized and I want to remove the oxidation layer with minimal damage to the polished surface. Any ideas? Help!
sam georges- Berkeley, California
December 1, 2009
How to remove the Oxidized Nickel from Ni Foil?
June 16, 2013Q. Hello
I have a problem on Ni foil.
It has partially darkened and I guess that this dark surface is result of oxidizing.
Someone said that I can remove this with using HCl and NaOH alternatively.
But I'm not sure it will really work and I don't know how it works.
Is there anyone who knows about this?
Thanks for your help :D
- Daejeon, South Korea
A. Hi Joonsap. If the thickness of this foil is not critical, the easiest and most reliable method may be to electroplate it with a Wood's Nickel Strike.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 23, 2013
Ohhh
Thanks for your advice!
Best Regards,
- Daejeon, South Korea
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