Determine if particles are aluminium oxide

I am getting a white dust in my car, coming from the air vents and landing all over, mostly on the dashboard. After searching about this, it seems that it could be caused by the fins of the air conditioner evaporator oxidizing (for whatever reason).


I recently bought the car (used), and I before I claim fixing/compensation from the dealer I want to have proof that it is in fact aluminium oxide, or else I expect that they will try every other alternative (=cheaper) explanation possible without getting to the root cause (seen this sooo many times).


So now I'm wondering if there is any reasonably cheap way to test and verify that the dust particles are aluminium oxide?




Aluminium forms a protective oxide layer that is strongly associated with the metal. Therefore, I doubt what you are seeing is actually aluminium oxide. Air probably wouldn't be able to disperse if.


In the case that I am wrong, though, there are several ways you can go about identifying whether or not the substance is aluminium oxide.


The first thing I would try is to drop in some water. Does it dissolve? If it does, definitely not aluminium oxide.


Firstly, since you wanna use this for insurance you wanna have it absolutely foolproof. You can subject a sample to mass spectrometry analysis. The downside is that it is expensive and you need to find a lab willing to analyse your sample.


Secondly, which is much more crude, you can subject it to metals and measure whether a reaction will occur or not. This can pinpoint where it is on the reactivity series, thus identifying the compound. For example, it may react with magnesium but not manganese. And this doesn't prove there is an oxide. It just proves it is an aluminium compound.


Research the reactivity series and redox reactions.


Thirdly, and this is also expensive, you can measure the melting point.


There are definitely other methods to doing this.


But I'm not sure this is a good idea in the first place. I don't think running a chemical analysis is a good way to make an insurance claim, but there is your answer.


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