INVESTIGATING THE CORROSION BEHAVIOR OF NANO STRUCTURED COPPER STRIP PRODUCED BY ACCUMULATIVE ROLL BONDING (ARB) PROCESS IN ACIDIC CHLORIDE ENVIRONMENT

• Main Authors: A. Nikfahm, I. Danaee, A. Ashrafi, M. R. Toroghinejad
• Format: Article
• Language: English
• Published: Iran University of Science & Technology 2014-06-01
• Series: Iranian Journal of Materials Science and Engineering
• Subjects: Ultrafine Grain; Corrosion; Copper; NaCl; Accumulative Roll Bonding; SPD
• Online Access: http://ijmse.iust.ac.ir/browse.php?a_code=A-10-127-49&slc_lang=en&sid=1

In this research accumulative roll bonding process as sever plastic deformation process was applied up to 8 cycles to produce the ultrafine grain copper. Microstructure of cycle 1, cycle 4 and cycle 8 investigated by TEM images. By analyzing TEM images the grain size measured below 100 nm in cycle 8 and it was with an average grain size of 200 nm. Corrosion resistance of rolled copper strips in comparing with unrolled copper strip was investigated in acidic (pH=2) 3.5 wt. % NaCl solution. Potentiodynamic polarization and EIS tests used for corrosion resistance investigations. The corrosion morphologies analyzed by FE-SEM microscopy after polarization test and immersion for 40 hours. Results show that the corrosion resistance decreased up to cycle 2 and increased after rolled for forth time. The corrosion degradation was more intergranular in cycle 2 and unrolled counterpart. It was more uniform rather than intergranular type in cycle 8. Corrosion current density in unrolled sample (2.55 µAcm -2 ) was about two times of that in cycle 8 (1.45 µAcm -2 ). The higher corrosion rate in cycle 2 in comparison with others was attributed to unstable microstructure and increase in dislocation density whereas the uniform corrosion in cycle 8 was due to stable UFG formation