Effect of grain size on corrosion of nanocrystalline copper in NaOH solution

Effect of grain size on corrosion of bulk nanocrystalline copper was investigated using potentiodynamic polarization measurements in 0.1 M NaOH solution. Bulk nanocrystalline copper was prepared by inert gas condensation and in situ warm compress (IGCWC) method. The grain sizes of all bulk nanocrystalline samples were determined to be 48, 68 and 92 nm using X-ray diffraction (XRD). Results showed that bulk coppers displayed an active–passive–transpassive behaviour with duplex passive films. From polycrystalline to nanocrystalline, grain size variation showed little effect on the overall corrosion resistance of copper samples.

Research highlights
► Coppers display an active–passive–transpassive behaviour with duplex passive film.
► Grain size variation has little effect on the overall corrosion behaviour of Cu.
► Little effect on corrosion may be due to duplex passivation in NaOH solution.
► Bulk nanocrystalline Cu show bamboo-like flake corrosion structure.