Corrosion analysis and characteristics of discarded military munitions in ocean waters

•Corrosion characteristics of discarded military munitions in seawater were studied.•β-Fe2(OH)3Cl was identified as the primary phase in the inner rust layer.•Fe3O4 and β-FeOOH were also detected in the inner rust layer.•A thick concretion layer formed outside of the β-Fe2(OH)3Cl layer.•The results can be used for future modeling efforts to predict DMM casing breaches.

The retrieval of discarded military munitions (DMM) from the seafloor of Ordnance Reef (OR), Hawaii after more than 60 years of exposure presented a unique opportunity to study and characterize the actual DMM corrosion morphology. An iron hydroxychloride was identified as the primary phase together with Fe3O4 and β-FeOOH in the inner rust layer on the projectile. A thick concretion layer consisting of an inner black FeCO3 layer and an outer grayish-white CaCO3 layer formed outside of the iron hydroxychloride layer. Iron sulphide was also detected in the black concretion layer, indicating the effect of sulphate-reducing bacteria.

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