On Nov 3, 2009, at 2:40 PM, Michel Jullian wrote:
As you certainly know the loading factor (hydrogen content) depends on the current density. If you have more current density on one side, you will have more hydrogen content on that side. And then by diffusion, you will have migration to the other side and desorption. Implacable, it's like trying to inflate a punctured tyre. Michel
I'd like to see a reference on that relationship. I don't think there is a linear relationship between loading flux and hydrogen evolution or current density. Hydrogen evolution in the form of bubbles is almost entirely the result of electronation, the tunneling of electrons across the interface. The tunneling probability is exponential in terms of the overpotential. When hydrogen is removed from the electrolyte side of the interface it drops the potential there. The solvated hydrogen concentration is dropped up close to the interface. The path for protons through the interface to the Pd is more linear in nature (compared to the electrons path in the opposed direction across the interface) with the overpotential because it requires a couple short distance proton tunnelings, and two water molecule rotations which are more linear with overpotential.
The metal side of the interface is clearly very close to the same potential everywhere. There ion conduction path to the back side covers many routes, but in the case of the mesh electrode is primarily through the mesh, a mm or less. In either case, the back side, or front side, the ion conduction rate is largely a product of diffusion and not potential gradient, at least in ordinary electrolytic cells, because most of the potential drop and vastly more gradient is at the interfaces. The field gradient between electrodes is so small that concentration gradients have more effect on the diffusion rates. However, it is unfortunately not clear at all what kinds of potentials and currents are involved. We are left to guess what is happening
As you can see, I have a very difficult time seeing that such a small change in potential can be responsible for that much "fusion". I may be highly biased though, especially by my work with anode discharges, which sound and look very similar, except in the visual range.
I find it concerning that the sound track on the film sounds very much like an electrospark experiment. It sounds like cavitation. The noise shows up when the cathode heats up, just like electrospark. I eventually started heating up my cells to boiling before starting (I was running a boiloff protocol) just to get more uniform and faster data. I think the cathode white dots may in part be steam bubbles.
Best regards, Horace Heffner http://www.mtaonline.net/~hheffner/
