Do you think that the unique structure of Raney Nickel survived flame spraying without changes?
Yes it did. Not at first - but with good technique it survives just fine. Got the idea from several different patents on using flame sprayed Raney Nickel to improve electrode efficacy in electrolysis.
Trick is to not allow oxidation, so it has to be a reducing flame, or add a shield gas. Using Oxyhydrogen generated via electrolysis is neither reducing nor oxidizing - and it makes a super fine torch flame. The surrounding transport gas for the raney powder was best to use pure Argon. And to purge the air in the powder feed tube/cup. Feed cup had a rubber stopper in opening so new air could not be entrained.
Before adding Ar as shield gas, the resultant coating was creating all kinds of aluminum oxides - a white deposit all over. But with shield gas there was only metal fused to the substrate, and then leaching the Al with KOH - leaves the micro structure you expect with Raney Alloy.
