While transition metal oxidation is generally "reversible" in the technical, electrochemical sense, in practice as a materials science problem with real world applications
in situ, the answer is "not so much."
The problem is that the structural shifts that occur during oxidation don't reverse simply by reversing the chemical change.
In solution, this isn't so-- it's a solid state issue.
This is the reason why electroplating isn't a DIY project from solution, in most instances.
Oxides generally aren't soluble enough in solution to allow for reversibility and 'replating' onto a surface once they fall off in a "spongy" or "columnar" form.
I know, this is probably way more than anyone wanted to know.
Occupational hazard.
This touches upon my DH's research expertise and the overlap with my own elecrochem background, so it's something he and I have discussed a lot over the past 25y.
