In the past few days I've been doing low-expectations, low-effort testing on a concept similar to that which started the thread - still electrolysis, but differently from usual LENR experiments, or "unconventional". Sometimes it looks as if the changes I'm doing are affecting Geiger readings, but as they can go either way or not act at all, and that they're of small magnitude compared to the background noise it could all be wishful thinking. Yesterday evening's "bump" (2019-02-24) seems unusual compared to the average for the past few days, however.
In short, I've set up a few bimetallic corrosion junctions using some of the metal pieces I used in past tests (washers, coins), two of which optionally heated at low temperature (about 40-45 °C). Occasionally I add 10% HCl electrolyte, which diffuses through the narrow gap. The one showing the highest voltage (measuring it precisely is difficult due to them short-circuiting when moved around, but I have observed a 300 mV peak with a multimeter) is an aluminium-mild steel one as shown in the photo below.
The aluminium heat sink here is at a positive potential (anode) relatively to the mild steel piece (cathode). Hydrogen gas is evolved in the process and I expect that on a small scale, large pressures within the materials (due to hydrogen ambrittlement) and the likely porous structures formed at the metal-metal junction may be formed. So, in principle this should not be too different than standard electrolytic experiments, only moving at a slower (possibly much slower) pace.
Interestingly, according to https://doi.org/10.1016/j.corsci.2012.10.032 the galvanic series ordering can be significantly affected by the electrolyte, so typical ones found on the internet for example for seawater might not be perfectly applicable to different conditions.
Abstract: Galvanic series of AISI 304, 316, 316L, and 316Ti austenitic stainless steels, AISI 410 and 420 martensitic stainless steels, 63Cu37Zn brass, Cu, Al, and AlMg1 were established for 10% (wt.) hydrochloric, phosphoric, sulphamic, sulphuric, nitric, citric, acetic, and methanesulphonic (MSA) acids used as cleaners in order to predict galvanic corrosion when coupling these materials. It was found that each acid has a distinctive order of metallic materials in a galvanic series. The largest corrosion potential difference in all acids exists between Al-based materials and stainless steels, as well as Cu-based materials indicating the use of Al-based materials as sacrificial electrodes.