TY - JOUR
T1 - A positron annihilation study of corrosion of aluminum and aluminum alloy by NaOH
AU - Wu, Y C
AU - Zhai, T
AU - Coleman, Paul G
PY - 2012
Y1 - 2012
N2 - Corrosion of fully-annealed pure aluminum and a continuous-cast AA2037 aluminum alloy (solutionized and water quenched) in a 1M NaOH solution for various periods of time were analyzed with positron beam-based Doppler broadening spectroscopy. By varying the energy of the incident positron beam, corrosion-induced defects at different depths from the surface were detected. It was found that the Doppler-broadened annihilation line-width parameter was significantly increased near the surface of pure aluminum after corrosion, probably due to the interaction between positrons and nanometer-sized voids formed near the aluminum surface during corrosion. Examination by atomic force microscopy indicated that many pits were formed on the aluminum surface after corrosion. In contrast, a significant decrease in the line-width parameter was observed in AA2037 alloy after corrosion and interpreted as being caused by copper enrichment at the metal-oxide interface during corrosion; such enrichment at large cavity sites was confirmed by energy dispersion spectrometry.
AB - Corrosion of fully-annealed pure aluminum and a continuous-cast AA2037 aluminum alloy (solutionized and water quenched) in a 1M NaOH solution for various periods of time were analyzed with positron beam-based Doppler broadening spectroscopy. By varying the energy of the incident positron beam, corrosion-induced defects at different depths from the surface were detected. It was found that the Doppler-broadened annihilation line-width parameter was significantly increased near the surface of pure aluminum after corrosion, probably due to the interaction between positrons and nanometer-sized voids formed near the aluminum surface during corrosion. Examination by atomic force microscopy indicated that many pits were formed on the aluminum surface after corrosion. In contrast, a significant decrease in the line-width parameter was observed in AA2037 alloy after corrosion and interpreted as being caused by copper enrichment at the metal-oxide interface during corrosion; such enrichment at large cavity sites was confirmed by energy dispersion spectrometry.
UR - http://www.scopus.com/inward/record.url?scp=84864582321&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1007/s11661-011-0806-9
U2 - 10.1007/s11661-011-0806-9
DO - 10.1007/s11661-011-0806-9
M3 - Article
SN - 1073-5623
VL - 43
SP - 2823
EP - 2831
JO - Metallurgical and Materials Transactions A
JF - Metallurgical and Materials Transactions A
IS - 8
ER -