iron oxide= rust aluminum oxide= corrosion
Big difference is rust is expansive in nature (can open up seams thus can cause leaks in metal to metal contact areas) and will continue to erode the iron as H20 and 02 find new Fe molecules to combine with. With aluminum it is much more stable with H20 and 02, but will form a very thin layer of aluminum oxide which by definition is corrosion. For those who have had the SIR impact sensor to body chassis fault issue know of this effect.
See.. those chemistry classes did have an effect on me
