G’day; I can state quite categorically that hydrofluoric acid cannot
produce nitrous oxide from stainless steel - or even nitric oxide. I
can find no on reactions between stainless steel and
hydrofluoric acid, and have no personal knowledge of a reaction.
Contrary to popular belief, HF isn’t really what one might call a
’powerful’ acid; it does react with human (and non human) flesh
producing ulcerous burns which don’t heal very well. It also
dissolves glass, quartz and silica, which no other acid does except
in minute quantities. It dissolves or reacts with a very few things
at all. Most metal fluorides aren’t too soluble in water anyway.
Superheated water at very high pressures does, go for stainless, but
then that reacts with literally everything - it is the Universal
Solvent the ancients were looking for. How else do agates and other
hydrothermal minerals get produced in nature? It even dissolves
gold and platinum, then deposits them when pressures and therefore
temperatures are reduced.
Boiling stainless with 10% sulphuric acid might remove the oxides
from heated stainless. Otherwise old fashioned abrasives will have to
do Cheers, –
John Burgess; @John_Burgess2 of Mapua Nelson NZ