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Topic: Colloidal Silica on Nickel Wire  (Read 2379 times)

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Offline jamieesibley

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Colloidal Silica on Nickel Wire
« on: February 13, 2013, 04:41:54 PM »
I have a only a moderate understanding of chemistry and I am trying to wrap my head around a process used to increase the surface area of fine nickel wires.

The steps listed are as follows:

1) Use a brush to apply aqueous solution of colloidal silica to the wire.
2) Heat the wire using its own electrical resistance to 400* C
3) Use a brush to apply the following mixture:  approximately equal aqueous parts colloidal silica, nickel nitrate,  phosphoric acid, and palladium nitrate.
4) Heat the wire using its own electrical resistance to 400* C

My questions are:

A) Does the colloidal silica become embedded in the wire (Steps 1,s) and then gets etched out (Steps 3,4) leaving a fissure or pit?
B) What are the effects of each of these chemicals on the wire?
C) Are these particular chemicals important? Can other oxidizers and acids be substituted?
D) How could this method me applied to nickel powder instead of nickel wires.
E) Does the wire pictured in the following URL, appear to have been treated with the above method?

Here are some electron microscope photographs of a wire that may have been treated with this process. 

http://www.quantumheat.org/index.php/follow/follow-2/118-sem-wire-characterisation

Thank you very much for taking the time to read this.

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