I did receive your email directly thank you Marshall and I replied to
you that I hoped you would post it for all to read. But as it didnt
appear, I figured I would post my own version with a few
'embelishments'. It seemed like a good idea at the time.
PS. I hope a subject appears on this. They just seem to dissappear
sometimes. My previous one was titled. 'Particle Theory - An Idiots
Tale'. (Referring to me of course)
David
* From: Marshall Dudley (view other messages by this author
<index.html?by=Author&a=Marshall%20Dudley>)
* Date: Wed, 27 Jul 2005 08:39:39
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I replied to this last week, but it seems to have not gotten on the list
(apparently it went to [email protected] instead, so here it is again:
alchemySA wrote:
Unless I've misunderstood things, the popular wisdom at the
moment seems to be that there are no real silver particles suspended in
low voltage CS. The theory goes that all these particles are really
just
compounds (e.g. oxides)
Where did you come up with that? Tyndall proves there are particles. The
color vs particle size proves they are pure silver particles as well. And
measurements I and many other have made using spectrophotometers and
disgestion chemistry proves it as well.
because the only silver is in the form of ions
that can't reform
into silver particles.
And why not, we see that happen all the time. The photographic process not
only proves it possible, but proves it to be easy and well understood.
We are also told that low voltage DC doesn't
have the
grunt to simply blast solid silver pieces off the wire.
That is true, silver ions move off the wire, and then combine to form
particles, that is why stirring and a low current are so important to
maintain small particle size.
But I was wondering if it's possible that as ions dissolve off the
electrode they occasionally 'undercut' chunks of solid silver that then
break off as tiny solid silver colloids. The same way that say a fallen
log slowly disintegrates in the forest. Some parts of the log virtually
dissolve or are eaten by termites, til eventually a bigger chunk of
timber just falls off.
That is possible, but not a likely mechanism.
I believe that electricity usually travels on the surface of the wire
(the path of least resistance?) but molten silver that's been rapidly
solidified and formed into wire would probably have plenty of weak
points that allow for undercutting ...maybe even gaps (alternative
'surfaces') that an electron can travel through.
Why would the silver be molten? Silver wire is formed by cold process
extrusion, there is no heat involved.
How else can particles be present in the water to plate the glass or
float as shiny flakes on the surface? (And are the flakes perhaps lifted
up there by a rare oxygen bubble that was created during, or mabe even
helped create, the aforementioned silver wire disintergration?)
Look up the photographic process, it is all well understood. Also the
silver will plate out on the cathode, producing wiskers and flakes.
Another explanation for these silver particles is that maybe silver ions
really can turn back into silver particles. All they need to do is to
pick up a loose electron from somewhere. How hard can that be? With
electricity running up and down both electrodes, and various chemical
reactions happening, there must occasionally be an electron that loses
it's way in all the excitement.
The solution is neutral, the silver ions are positive, the OH and O2 is
negative. I have posted the eqauations for this many times to this forum.
They can easily do this, once again look up and understand the photographic
development process to see how easy and well known this is.
Finally, when the experts dry the CS and do photos with TEMs or SEMs or
whatever, can they really sort the wheat from the chaff? Can they
really pick the oxides from the particles (if there are any) or do they
all look the same?
They do not look the same, but as you evaporate the water, the composition
can change, so it is hard to say for sure what you started with.
Marshall
David
