Zinc-Rich Organic Systems Exposed Five Years to a Marine Atmosphere
Final technical rept. 1967-1972
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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Zinc-rich organic primers, with and without topcoats, were exposed for 5 years in the tropical marine atmospheric environment of Kwajalein, Marshall Islands, and Kaneohe, Hawaii, and at Port Hueneme, California. Satisfactory protection to steel test panels was given by two- and three-package zinc-rich epoxy primers, and a zinc-filled modified saran coating. An alkyd enamel was found to be a very good topcoat when applied directly over the zinc- rich primer. A silicone alkyd was found to give outstanding protection as a topcoat. A modified saran containing 3.1 to 5.3 pounds of zinc dust per gallon, with or without a modified saran topcoat, gave excellent protection to the steel test specimens. Zinc-rich epoxy primers are recommended for replacing primers containing toxic lead oxide or chromate pigmentation. The degree of protection of metal substrates by coating systems exposed to severe tropical marine atmospheric environments for 3 to 5 years can be used as the criterion for predicting good to superior performance by coatings.
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