Sciencemadness Discussion Board

metal nodules / crystals by electrolysis

me2 - 17-10-2012 at 05:53

Hi,

On the wiki-page of Nickel I encountered this image

http://en.wikipedia.org/wiki/File:Nickel_electrolytic_and_1c...

the description says :

"Electrolytically refined pure (99.9 %) nickel nodules, and a high purity (99.99 % = 4N) 1 cm3 nickel cube for comparison. Crystallized nickel-electrolyte salts (green) can be seen in the pores of the nodules"

So, this modules were made bij electrolysis of a Ni-salt. How is that possible ?? Every metal I saw on the cathode (except Zn) is just pain 'mud'. Very fine crystals, nothing like this.

So how would you attempt making these ones ?

note : These electrolytical noduls appear of other metals too. I found nodules of Mg, Cu and Pb.

[Edited on 17-10-2012 by me2]

[Edited on 17-10-2012 by me2]

tetrahedron - 17-10-2012 at 05:57

you need the right electrolyte composition, otherwise the reduced Ni won't stick together. these nodules also appear in commercial nickel plating as an unwanted phenomenon, due e.g. to irregularities in the cathode (part to be plated).

me2 - 17-10-2012 at 06:02

Quote: Originally posted by tetrahedron  
you need the right electrolyte composition, otherwise the reduced Ni won't stick together. these nodules also appear in commercial nickel plating as an unwanted phenomenon, due e.g. to irregularities in the cathode (part to be plated).


tnx. Next question. Which electrolytes will make such nodules and which not?

Is the electrolyte itself being reduced ? If so these nodules wouldn't be 99% pure. So I guess there must be something else ?

Do you know how this phenomenon is called? (if it has a name) So I can google the term myself.

edit : just a remark. Many industrial electrolysis use liquid metal-choride to obtain the meatl and chloride gas. In first instance I thought this would be the origin of these nodules. But because the description I think these are made different.

Quote:

Crystallized nickel-electrolyte salts (green) can be seen in the pores of the nodules



[Edited on 17-10-2012 by me2]

hissingnoise - 17-10-2012 at 06:07

And in plants chrome-plating hand tools!
Chromium is applied to a pre-plate of nickel . . .
The deposits can often look like metal dentures!


tetrahedron - 17-10-2012 at 06:46

google nickel plating. try this to get 99% purity: http://www.freepatentsonline.com/3755113.pdf

[Edited on 17-10-2012 by tetrahedron]

me2 - 17-10-2012 at 07:04

Quote: Originally posted by tetrahedron  
google nickel plating. try this to get 99% purity: http://www.freepatentsonline.com/3755113.pdf

[Edited on 17-10-2012 by tetrahedron]


thank you very much !

In a quick search the same image showed up in this page about sulfamate nickel plating ... I think I can start experimenting :D

But this doesn't need to be the end of this thread :P If any have more suggestions (other metals) or remarks, just shoot

12AX7 - 17-10-2012 at 16:11

Thiourea is another common additive, at least for copper. It probably works with nickel too. A few drops of something which contains it, such as Tarn-X, will turn your deposits from crystalline dross to flat (or lumpy!) dense deposits. More sophisticated (and secretive!) additives are similarly in the "leveler" and "brightener" category; some can apparently create a nearly mirror finish direct from the bath.

Tim