LOCALIZED CORROSION OF ALUMINUM ALLOY 2024 EXPOSED TO SALT LAKE ATMOSPHERIC ENVIRONMENT IN WESTERN CHINA

Localized corrosion behavior of aluminum alloy 2024 with/without cladding exposed to salt lakes atmospheric environment in western china for 4 a was investigated.The depth of pitting,corrosion products,morphology of surface and cross-section,and corrosion potential were analyzed by SEM/EDS,OM,XRD and electrochemical analysis system.The results showed that 2024 suffered severe pitting corrosion.The cladding layer of aluminum alloy 2024 exposed for 2 a had been penetrated.Depth of pitting of aluminum alloy 2024 without cladding after 2 a exposure had reached 320 urn;meanwhile,few pitting that penetrated the whole substrate of aluminum alloy 2024 without cladding had been observed.A main corrosion product of aluminum alloy 2024 with/without cladding—[Mg_(1-x)Al_x(OH)_2]~(x+)(Cl~-,CO~(2-))_x·mH_2O(layered double hydroxides,LDH) was determined.Also,the results of electrochemistry indicated that the corrosion potential of aluminum alloy 2024 decreased gradually with the concentration of Cl~- increasing.The effects of factors of salt lake atmospheric environments,corrosion product and Cl~- concentration on the corrosion behavior of 2024 with/without cladding were discussed.