Bring to the boil and just dip a piece of Al in (Briefly) it will turn a dirty grey colour. That is a coating of Al203 stuck very firmly in place. The longer you leave it in the more complete the coating, brief exposure gives a porous coat.
I keep wondering:
1. water being in the presence of porous oxide structure while developing the layer as per Alan's hint of mild KOH boiling solution dip or
2. boiling water being used to seal the pores of anodization layer via electrolysis in acid
What if water is trapped in the layer and what if CPs are interacting with water molecules, especially hydrogen, rather then aluminium or oxygen, thus increasing the catalyzing effect for a chain of possible fusion and fission events starting with hydrogen?
Matsumoto: did he use potassium based electrolyte? KOH/K₂CO₃? Does potassium or carbon play a role? I recall Bob Greenyer mentioning potassium, need to dig in.
Shoulders: no hydrogen here: silicon carbide over aluminium oxide over aluminium? Silicon, carbon? https://www.lenr-forum.com/att…tion-ken-shoulders-1-pdf/
Edit: Andrija Puharich allegedly ran his car "on water" not knowing the energy source was CP-catalyzed fusion? Later Stanley Meyer did the same?
Puharich underlines the porous ceramic coating being key:
I recall Meyer replicators talking about electrode conditioning being key, where they build up a semi-insulating coating on the cathode I guess from materials within electrodes and the local tap water.