Pure Al does form a passive layer, but apparently not 2024 Al alloy as used on aircraft (trades more strength for corrosion susceptibility). https://en.wikiped

Pure Al does form a passive layer, but apparently not 2024 Al alloy as used on aircraft (trades more strength for corrosion susceptibility). https://en.wikipedia.org/wiki/2024_aluminium_alloy https://en.wikipedia.org/wiki/2024_aluminium_alloy Some corrosion pics still at http://connielinguscorrosion.blogspot.com/ http://connielinguscorrosion.blogspot.com/ .