Breakdown of metal passivation layers

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The discussion revolves around the corrosion of aluminum when subjected to a voltage difference in an ionic solution, specifically focusing on the removal of aluminum oxide prior to corrosion. The initial query seeks to understand the voltage required to remove the oxide layer and the kinetics involved in this process. Participants suggest that theoretical models may be limited due to numerous variables, advocating for experimental approaches instead. There is also interest in identifying metal oxides that are most effective for passivating electrodes in ionic solutions, with a call for methods to determine the best materials for this purpose.
Excom
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Hi All

I hope that someone where can help me out.

Let's assume that we take a piece of Al foil and a Pt wire and put them into an ionic solution. We then apply a voltage difference of 2 V between the two. Al(+) and Pt(-). After a few seconds the Al electrode starts to corrode. Nothing new about that but can anyone tell me what happens before the corrosion starts? I assume that the aluminum oxide is being removed. I am interested in figuring out what voltage that is needed to remove the aluminum oxide. And the kinetics of it.

If this can be described in a theoretical manner I will prefer that as I would like to compare different metal oxides at different voltages.

Thanks

Best regards
Tom
 
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Way too many unknown factors for a theoretical treatment, experiments are a way to go.
 
Okay, thanks.

Instead of testing every metal oxide there must be a way of finding those oxides that are most likely to be the best.

Any idea of how to this?
 
Excom said:
to be the best

In what sense?
 
I want to find the best materials for passivating electrodes in ionic solutions.
 

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