woelen - 9-10-2006 at 01:41
I intend to buy platinum wire for electrolysis purposes, for making KBrO3, KClO3 and KIO3 from the halide salts. I now use carbon rods for this, but
I'm getting quite sick of all the black crap from these things and also the impurities I get from the linseed oil. I always get yellow stuff. Now I
want platinum wire for better results.
I have found different types of platinum wire:
* 99.9+% platinum wire, or even 99.99% wire
* 95% platinum, 5% iridium wire
* 92% platinum 8% tungsten wire
Also, I have seen wire with thickness of 0.40 mm, 0.25 mm and 0.005 mm. The latter is much cheaper, but also very thin. Which diameter would be best?
I wonder which is the best for electrolysis purposes. All types of wire have approximately the same (high 
) price, only the 99.99% wire is much more expensive than all other types of wire.
So, which wire I can best purchase?
The prices are appr. $2 per cm for wire with a diameter of 0.25 mm, $4 per cm for wire with a diameter of 0.4 mm. The 0.05 mm wire has a price of
$0.20 per cm. Are these reasonable prices or is the supplier ripping me?
[Edited on 9-10-06 by woelen]
Jdurg - 9-10-2006 at 04:41
Even platinum wire will weaken a bit as electrolysis takes place, so the thicker the wire the more sound your electrode will be. However, as you
increase the thickness of the wire you also increase the resistivity of it a bit so you need to pump more electricity through it. I would avoid the
0.005 mm wire since at the voltage and amperages being used it will significantly weaken the physical structure of the wire. (I believe the 0.005 mm
wire is designed for low voltage/low amperage circuits).
Basically, the thicker the wire the more safely it is able to carry higher currents but the less effective it is at transmitting that current. The
lower the thickness, the less safe it is at carrying those currents but the more of that current that reaches your solution.
YT2095 - 9-10-2006 at 06:31
I`de also choose the 0.4mm (where cash allows).
just out of curiosity though, how does the price compare with the 99.9% and the Ir alloy?
if it`s Favorable significantly, then I`de go the Iridium route personaly.
Fleaker - 9-10-2006 at 06:52
Have you considered titanium as a substitute?
The pure platinum will be much much softer than the Pt/Ir alloy and the Pt/W alloys and probably easier to work with if you want to roll out a piece
for increased surface area. Have you considered dissolving platinum and putting it down on a substrate of some kind?
12AX7 - 9-10-2006 at 09:04
Titanium is no good for anode, it rectifies.
TIm
chromium - 11-10-2006 at 10:27
Does anyone know why other noble metals are not used for anodes? Palladium and iridium are much cheaper and should be quite inert.
Btw platinum can be plated to other metals. Plating on titanium is used in industries to make anodes. Platinum layer of only 0.15 micron thicknes is
said to be enough for most purposes.
[Edited on 11-10-2006 by chromium]
Fleaker - 11-10-2006 at 12:49
Palladium isn't that inert and iridum is almost impossible to extrude into wire, the fabrication costs make it prohibitively expensive. It may be 550/
oz Ir versus 1200 for platinum, but platinum is much more easily worked.