✔ 最佳答案
In anodization of aluminium, Al anode is actually oxidized to Al(III) in the form of Al2O3. Therefore, a thin layer of Al2O3 is coated on the surface of the Al anode after the anodization.
In the process, Al anode is firstly oxidized to Al3+ ion :
Al → Al3+ + 3e-
Since Al3+ is a very small ion carrying 3 positive charge, it has a great polarization power to react with water to give Al2O3.
2Al3+ + 3H2O → Al2O3 + 6H+