Corrosion protection of ion vapor deposition (IVD) Al-coated Al alloys by low-temperature plasma interface engineering - Part I. DC cathodic polymerization with anode magnetron enhancement

Anode magnetron enhanced DC cathodic plasmas were used to treat ion vapor d eposition (IVD) aluminum-coated 2024-T3 and 7075-T6 Al alloys for the creat ion of plasma interface-engineered systems of IVD/plasma polymer/primer. Ca thodic electrocoat (E-coat) and three kinds of spray paints were employed a s primers. Plasma treatment and polymerization on IVD Al-coated Al alloys p rovided an excellent adhesion base for succeeding primer coatings; extremel y strong, water-insensitive adhesion was obtained between the plasma-treate d IVD Al-coated Al alloys and primers. When evaluated by SO2 and prohesion salt spray tests, these plasma interface-engineered IVD/plasma polymer/prim er systems showed excellent corrosion protection characteristics. After 4 w eeks of SO2 salt spray testing, these plasma coating systems outperformed t he two types of controls used in this study, i.e., chromate conversion coat ed and then cathodic electrocoated (BASF E-coat) or chromated primer (Deft 44-GN-36) coated IVD Al alloys. After 12 weeks of Prohesion salt spray test ing, the plasma interface-engineered IVD/plasma polymer/primer systems show ed corrosion test results comparable to the Deft primer-coated controls and outperformed the BASF cathodic electrocoated controls. (C) 2001 Elsevier S cience B.V. All rights reserved.