The microstructures and corrosion properties of polycrystalline copper induced by high-current pulsed electron beam

In order to investigate the corrosion mechanism of pure metal materials containing little impurities, polycrystalline commercial pure (cp) copper was irradiated by high-current pulsed electron beam (HCPEB). The surface microstructures of irradiated samples are characterized by using optical microscopy and transmission electron microscopy (TEM). The corrosion resistance is also investigated by using polarization curves of seawater corrosion and electrode impedance spectroscopy (EIS). The experimental results indicate that the corrosion resistance of cp copper irradiated by 10 pulses is remarkably improved comparing with the original sample. TEM observations suggest that large amount of supersaturated vacancy defects are produced when the material surface is subjected to the HCPEB irradiation. Furthermore, the agglomerations of the vacancy defects cause the formation of the vacancy cluster defects, such as vacancy dislocation loops, the stacking fault tetrahedra (SFTs) and voids. It is suggested that the structural defects on the irradiated surface have some relationships with the corrosion resistance's improvement of the material.