Historical research guide · 0403 · 2020

Electrochemical loading to produce the Fleischmann-Pons heat effect (FPHE)

Michael C.H. McKubre

In one minute

Michael McKubre spent decades at SRI International measuring the Fleischmann-Pons heat effect, and this chapter is his account of the thing that has to go right before anything else can: getting deuterium into palladium and keeping it there. Loading is counted as a ratio, deuterium atoms per palladium atom, and McKubre’s central finding is that the highest ratio a cathode ever reaches in its life predicts, better than any other single number, whether that cathode will make heat. Plot excess energy against loading and the shape is roughly a bell rather than a step above a threshold — which he reads as a hint that the effect may need two phases of palladium deuteride present together, so the target could be a window of composition rather than a floor to climb past. From twelve closely matched electrolysis runs he pulls out the two parameters that decide it: how sound the bulk metal is, and the electrochemical state of its surface, including additives and current density.

Connection

Chapter 12 turns on whether a metal lattice can be driven into the state where its nuclei do work, and McKubre’s answer is that the state is a loading state you have to enter deliberately. For chapter 1 this is the most useful kind of evidence there is about reproducibility: the effect is not capricious, it is conditional, and the chapter names the conditions and the two parameters that control them.

From the source

Loading palladium with deuterium into the regime where a cathode can be made to generate power in excess of all known inputs requires careful control of a large number of variables. Entering that region of composition at all is the central practical problem, before any question about the reaction itself.Chapter abstract, opening; Chapter 3, pp. 37-54
The maximum loading a cathode reaches at any point in its history correlates closely with its propensity to produce excess heat. It is the best single predictor in the data set.Chapter abstract, second sentence
The relationship between excess energy — the integral of excess power over the run — and loading has a somewhat Gaussian form rather than a simple threshold. McKubre’s reading is that the environment producing excess heat may require two phases of palladium deuteride to coexist, in which case the effect should be sought in a range of prepared deuterium-to-palladium stoichiometries rather than above a single value.Chapter abstract, third and fourth sentences
Analysis of a single set of twelve closely comparable experiments using palladium cathodes in lithium deuteroxide, with one in ordinary lithium hydroxide, shows two parameters to be paramount: the condition of the bulk palladium, and the electrochemical condition of the interface between palladium and electrolyte, including additives and current density.Chapter abstract, fifth sentence
Because deuterium moves through palladium so freely, partial success is no use. The surface must be in the desired electrochemical condition everywhere at once, and the bulk metal must be homogeneously sound throughout, or the loading leaks away wherever it is not.Chapter abstract, sixth sentence
McKubre’s stated conjecture is that only cathodes sound in both surface and bulk can sustain high loading at the high current densities thought to be needed to initiate excess heat production — which makes metallurgy, not chemistry, the gate on the experiment.Chapter abstract, closing sentence

The way in

https://doi.org/10.1016/b978-0-12-815944-6.00003-8

Historical source-access record. This guide links to the original; it does not reproduce the paper text.

Chapter 3, pages 37 to 54, of Cold Fusion: Advances in Condensed Matter Nuclear Science, Elsevier, 2020, ISBN 9780128159446. The chapter is closed at the publisher, whose deposited licences are the Elsevier text-and-data-mining user licences rather than any licence to readers, and the publisher’s site refuses automated readers, so none of its text is reproduced here. The summary and claims below were written from the author’s own chapter abstract as deposited by the publisher and read in full, together with the surrounding record of Michael McKubre’s loading work at SRI International. The chapter is 18 pages. Two companion sheets are read with this one, both on the co-deposition route that gets to a loaded electrode in seconds rather than weeks: Stanislaw Szpak’s account of the method at /library/stm-344232fcb0, and the Szpak, Mosier-Boss, Miles and Fleischmann calorimetry at /library/stm-f6651a4d1a.

How to cite it

Michael C.H. McKubre (2020) Electrochemical loading to produce the Fleischmann-Pons heat effect (FPHE) doi:10.1016/b978-0-12-815944-6.00003-8

Where it sits in the curriculum

Lattice confinement fusion