The filiform corrosion susceptibility of extruded, chromated and coated AA
6060/6063 alloys has been investigated. It is shown that, provided sufficie
nt metal is removed before chromating, these alloys will exhibit high filif
orm corrosion resistance. In those cases where extensive filiform corrosion
attach is observed during corrosion testing it is shown to be due to a rea
ctive surface region, formed during the thermo-mechanical processing of the
alloy and remaining after chemical pretreatment for painting.