ASTM B 117 Screening of Nonchromate Conversion Coatings on Aluminum Alloys 2024, 2219, 5083, and 7075 Using DOD Paint Systems

Report No. ARL-TR-2907
Authors: Brian E. Placzankis, Chris E. Miller, and Craig A. Matzdorf
Date/Pages: April 2003; 40 pages
Abstract: This study examines corrosion resistance of eight nonchromate conversion coatings vs. hexavalent chromium based Alodine 1200S controls on scribed coated test panels of aluminum alloys 2024, 2219, 5083, and 7075. Five representative Department of Defense primer/topcoat organic coating systems were evaluated for each of the conversion coating/alloy combinations. Scribed panels were exposed using ASTM B 117 (neutral salt fog) for 3000 hr and were photographed and measured at 1, 2, and 3 weeks. Subsequent measurements were taken every 500 hr until ?3000 hr? was reached or until failures from scribe creepback and/or via blistering occurred using method ASTM D 1654. Differences in pretreatment performance based upon variation in coating type as well as alloy were noted. Relationships between data from this study and data collected from previous cyclic acceleration corrosion exposure and how they may relate with respect to implementation of nonchromate pretreatments for various military applications are discussed.
Distribution: Approved for public release
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Last Update / Reviewed: April 1, 2003