• Glenn, Matthew
• Wilson, Nick
• Lau, Deborah
• Hughes, Tony
• Torpy, Aaron

Abstract

The effect of electron beam induced carbon contamination on the corrosion behavior of aluminum alloy 2024-T3 (AA2024-T3) has been investigated using immersion and polarization-type corrosion tests. For the immersion test, carbon was deposited on a polished surface of AA2024–T3 in the form of concentric squares increasing in thickness toward the center. The sample was then corroded in 0.1 M NaCl for 80 hrs at room temperature and subsequently examined in a scanning electron microscope (SEM) to determine how the matrix and intermetallic phases behaved under the contamination layer. Results indicated that only the longest contamination time (16 hours) produced significant corrosion inhibition. Within this region corrosion was largely limited to pitting of some intermetallics. Outside this region inhomogeneous corrosion, significant pitting and variable matrix etching were observed. For the polarization test, a multi electrode sample was prepared containing 20 electrodes of pure aluminum wire embedded in carbon doped epoxy resin and polished to 0.25 μm finish. The electrodes were given electron beam exposure times of up to 64 hours and then given a standard polarization test. Results indicated that corrosion inhibition increased with increasing electron beam exposure time, although even the shorter electron beam exposures resulted in significant inhibition.

Topics

• surface
• Carbon
• corrosion
• phase
• scanning electron microscopy
• aluminium
• etching
• intermetallic
• resin
• wire
• pure aluminum