Effect of Grain Size on Pitting Corrosion Behavior of Copper
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Graphical Abstract
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Abstract
Circular polarization and electrochemical impedance spectroscopy(EIS)were used to analyze the effect ofdifferent grain sizes on the pitting corrosion behavior of fine copper.Optical microscopy,scanning electronmicroscopy(SEM)and electrochemical workstation were used to analyze the surface properties of copper specimenswith different grainsizes in three kinds of solution.The results indicate that active dissolved pitting corrosion of Cuoccurred in SO42-/HCO3-mixed solution,the pitting sensitivity of Cu increased with the reduction of grain size;but in the alkaline solution with OH-,the reduction of grain size promoted the formation of the protective passivefilm which owns fine self-healing capacity.SO42-led to the film rupture of Cu in the alkaline solution with OH-.The smaller the grain size,the weaker the pitting sensitivity of Cu surface.
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