Magnesium automotive paint flaking failure

Why deck lids and hood lids are aluminum, not magnesium — atmospheric corrosion under paint.

So you don't like magnesium anywhere it's exposed. You can't even use it for deck lids — that's what they do for aluminum on automobiles. They make the rear hatch door or the hood lid out of aluminum, bolt it onto the rest of the steel structure, paint it, and aluminum's got good corrosion resistance — it's just fine. You don't do that with magnesium, because even just a little bit of atmospheric corrosion underneath, and the paint starts flaking off after four or five years. Not with aluminum. Aluminum's got better corrosion resistance than steel. It's rusty steel causing the paint to flake off on automobiles.