引用:
原帖由 match_man 於 9-3-2008 18:58 發表
Aluminium-不是只會oxidize但不會rusting 嗎?
but Aluminium has strong resistance towards corrosion ....
我估唔係corrosion....因為本身Aluminium 外面有一層stable的Aluminium 3+ ions 的protective coa ...
concept correct but not accurate enough
Aluminium is actually a quite reactive metal
In contact with air, aluminium will be oxidized to Aluminium oxide (Al2O3)
Aluminium oxide, unlike rust, is not porous, therefore it cannot allow air or water or salt to penetrate it to react further more with aluminuium
That make aluminium oxide a protective layer of aluminium layer.
Al2O3係ionic compound, 不過佢唔係以ion form黎保護aluminium架
