CORROSION RESISTANCE, ELECTRICAL CONDUCTIVITY AND ADHESION CHARACTERISTICS ON MATERIAL-COATINGS AND ADHESION CHARACTERISTICS
GENERAL DYNAMICS CORP POMONA CA POMONA DIV
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Twelve commercial chemical conversion coatings for Al, which conform with Mil-C-5541 requirements, were evaluated when applied to 2024-T3 clad and bare, and 7075-T6 clad and bare Al alloys. Salt spray, 100 relative humidity and atmospheric testing were done with coated, coated and lacquered, and galvanically coupled Type 301 stainless steel specimens. The electrical conductivity of the various coatings was determined by resistance measurement. Paint adhesion was determined by impact shock resistance methods. Wide variations were not found in the corrosion protection afforded by the several materials although Alodine 600 offered a slight advantage. Appreciable reductions in the electrical conductivity of surfaces resulted from chemical conversion film application. These reductions tended to be specific with each Al alloy surface responding best to a specific proprietary coating. Impact shock tests with a wash prime-ZnCrO4 lacquer primer-lacquer topcoat paint system indicated better adhesion with Alodine 1000 and Bonderite 710 chemical films.
- Coatings, Colorants and Finishes