Corrosion behaviour of nanocrystalline copper

With increasing applications for nanocrystalline materials, it is important to determine the effect of grain size on corrosion behaviour. In this thesis, the corrosion behaviour of commercially available copper foils (cold-rolled annealed and electrodeposited) were compared with electrodeposited copper foils with various grain size ranging from 45nm to 1000nm. Potentiodynamic polarization testing in 0.1M NaOH and 0.1M NaCl were performed to determine the passivation and active dissolution behaviour of nanocrystalline Cu, respectively. Corrosion morphologies were analyzed with SEM/EDX to determine the susceptibility of localized corrosion. It was found that grain size reduction had a negligible effect on polarization results in both 0.1M NaOH and 0.1M NaCl solutions. SEM/EDX analysis revealed similar corrosion product morphologies for all the materials in 0.1 M NaOH solution which suggests that the passivation characteristics are not affected by surface disorder. In 0.1M NaCl solution, a pitted corrosion morphology was observed with more but smaller pits as the grain size decreased.