At 03:52 PM 11/3/2009, Horace Heffner wrote:
If SPAWAR is running with a fixed current supply and they plate out
all the PdCl electrolyte, then the voltage across the cell could be very high.
There is LiCl2, or other salt, in the electrolyte to keep it
conductive. Galileo protocol and, I think, much of their work is with LiCl2.
I don't think this is right. I think the interface will be about
the same on both sides. The potential drop through the mesh has
little practical effect. If you look at ordinary cathodes in
electrolysis, even big ones, they evolve hydrogen on both
sides. Have you ever seen a cathode evolve gas on only one side?
That might depend on the path length. The rate of evolution should be
directly proportional to the current density.
At first, a nickel mesh would presumably generate gas on both sides,
except that if one side is in contact with the mylar, there would not
be electrolyte there, or not as much, and the resistance per mm would
be higher, so less current density there. However, if the mesh fills
up with palladium deuteride, the path length around it lengthens,
plus that whole side is against the mylar in that experiment.
Am I correct that what they are actually seeing is the mylar temperature?
In any case, from other evidence, we know that the local temperature
at reactions sites apparently exceeds the vaporization temperature of
palladium deuteride, whatever that is. Hot. The IR camera is maxed
out at something like 20 degrees C, the way that it's set, if I
remember correctly.
I think we are seeing the back side, the palladium deposit and the
nickel mesh rapidly transmit the temperature increase to the back
side. The back side isn't evolving deuterium, or not evolving much,
because it's up against the mylar, it's the "contact surface" mentioned.
