Electroactive polymer coatings as replacements for chromate conversion coatings

NAVAIR-WD has successfully synthesized an electroactive polymer, poly(2,5-bis(N-methyl-N-hexylamino)phenylene vinylene), (BAM-PPV) in high yield and purity. BAM-PPV has also been characterized using advanced spectroscopic, electrochemical and thermal analysis techniques (NMR, FTIR, ENM, TMA, DSC and TGA) to determine its structure, corrosion prevention mechanism, mechanical and thermal properties, respectively. BAM-PPV coated aluminum samples have repeatedly survived 336 hours neutral salt fog spray exposure (ASTM B117), which is a current military requirement for alternatives to chromate conversion coating (CCC) pretreatments. Testing the polymer system as a conversion coating under neutral salt fog conditions with full military coatings has also been performed. The scribed BAM-PPV Al 2024-T3 coupons with a non-chromate primer and topcoat showed evidence of corrosion at 2000 hours. Coupons with BAM-PPV as the pretreatment with a chromated primer and a topcoat showed no corrosion along the scribed areas after 2000 hours of salt fog exposure. These were compared to a fully chromated system which also showed, no corrosion along the scribed area at 2000 hours of exposure.