Dodoman
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Rhodium solution
Hi to all
I wanted to prepare a rhodium solution for electroplating but unfortinetly i don't have enough info on the subject.
I think the rhodium would be present as a salt but i don't know what type of salt and what effect would it have on the plated metal (well that
can be pridicted anyway).
But most importently at what concentration is the salt present in the solution? (very important form an economical point of view).
Are there any surfactants in the solution? If so what kind and what effect does it have?
Can the solution be prepared from the metal by dissolving it in an acid and nutrelizing the solution? If so what acid would dissolve it?
I didn't realise that i had so many question untill i wrote the post. So anyways. Any help would be apretiated and thatnx in advance.
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guy
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I think it could be any salt as long as its soluble.
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Dodoman
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Well i think that some salts are better that others. For example after excesive electrolysis the anion would be present in excess which would easly
form an acid. I don't think the acid will attack the metal or the thin newly forming layer of Rhodium though (due to the electric current
applied). But it could have a bad effect on the electrodes. Please correct e if i'm wrong.
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guy
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Have the anode out of rhodium. Rhodium will be plated on the cathode, the other rhodium electrode will disslove due to electrolyis and continue to be
plated on the cathode. Its kind of like electrorefing with copper.
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BromicAcid
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Rhodium is usually plated from strongly acidic solutions. Here is a good google groups thread on the subject. the sulfate is usually used but other anions can probably be present with no major
complications, it depends on what you are plating. As for the concentration, due to rhodium being such a noble metal it plates out preferably to most
metals and unless it is in terribly small concentrations it should always plate. Being that most rhodium salts are colored it should be easy to
monitor if you have sufficent rhodium in solution to plate, if it gives a decent color it should plate. I would think....
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Dodoman
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| Quote: | Originally posted by guy
Have the anode out of rhodium. Rhodium will be plated on the cathode, the other rhodium electrode will disslove due to electrolyis and continue to be
plated on the cathode. Its kind of like electrorefing with copper. |
Yes but have you practically plated copper. I have and the new layer of copper doesn't hold on the electroplated metal. It forms like a thin
layer of powder that falls of when you touch it. I wouldn't like to have the same problem with Rhodium.
Thank you Bromic for the link. Do you know what are the organics (brighteners, wetting agents, de-bubblisers) he was refering to ?
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Dodoman
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I found this. But still don't know what are these organic Primary and Secondary Addition Agents are in specific.
The site also contains a typical formulas for rhodium plating.
[Edited on 2-11-2004 by Dodoman]
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