Corrosion Behavior of Ultra Fine Grain Copper Produced by Accumulative Roll Bonding Process

A. Nikfahm, I. Danaee, A. Ashrafi, M. R. Toroghinejad

Corrosion Behavior of Ultra-Fine Grain Copper Produced by Accumulative Roll Bonding Process

Transactions of the Indian Institute of Metals ,February 2014, Volume 67, Issue 1, pp. 115-121

Abstract

In this study the effect of microstructure changes on the corrosion behavior of pure tough pitch copper in 3.5 % NaCl solution with pH = 5.5 at ambient temperature was studied. Accumulative roll bonding process as severe plastic deformation was applied up to 8 cycles to produce the ultrafine grain copper. For corrosion resistance investigations, the polarization and electrochemical impedance spectroscopy was used. Corrosion morphologies analyzed by FE-SEM microscopy after polarization and immersion tests. Results show the minimum corrosion resistance for cycle 2 and maximum corrosion resistance for cycle 8. Corrosion rate of copper decreased after it was rolled for forth time. The corrosion degradation in cycle 8 was uniform and it was intergranular for sample of cycle 2 and unrolled counterpart. The higher corrosion rate in cycle 2 was attributed to unstable microstructure and the uniform corrosion of cycle 8 was due to ultra fine grain formation.