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Wednesday, March 19, 2008 - 9:55 AM
Convention Center, Second Level, R09 (Ernest N. Morial Convention Center)
08232
Pitting Corrosion Study in an AE44 Magnesium Alloy
The initiation and growth mechanisms of corrosion pits in an AE44 magnesium alloy, subjected to a wet saline environment, were quantified, and a corrosion mode to explain the phenomena is suggested. Immersion test were carried out in a NaCl 3.5% solution, for different surfaces at room temperature. The corrosion process was evaluated using a laser profilemeter (LP), optical microscopy (OM ), scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS). The stereological quantities included the pit density number, pit radius, pit size distribution, and pit coalescence area. A pit corrosion evolution was estimated using the data obtained from the laser Profilemeter.
The study found two different corrosion modes: general corrosion, localized pitting, followed by pit coalescence. General corrosion is caused by dissolution and regeneration of a protective film in the presence of chloride salts, while the localized corrosion begins as the result of the preferential dissolution of Magnesium due to the galvanic cell. General corrosion occurred during the whole experience, whereas localized pitting was dominant at the beginning of the exposure, followed by pit coalescence prevailing over longer time periods.
The study found two different corrosion modes: general corrosion, localized pitting, followed by pit coalescence. General corrosion is caused by dissolution and regeneration of a protective film in the presence of chloride salts, while the localized corrosion begins as the result of the preferential dissolution of Magnesium due to the galvanic cell. General corrosion occurred during the whole experience, whereas localized pitting was dominant at the beginning of the exposure, followed by pit coalescence prevailing over longer time periods.
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See more of The CORROSION 2008 Conference and Expo (March 16-20, 2008)