Five kinds of pure aluminum were prepared by spark plasma sintering using different grain size ofaluminum powders as raw material. The effect of grain size on corrosion and passivation properties ofthese kinds of aluminum was investigated by potentiodynamic polarization, electrochemical impedancespectroscopy (EIS), Mott-Schottky test and immersion test. The results revealed that fine grainaluminum showed a bigger passive current density than those containing coarse grains. The corrosioncurrent density at OCP also increased with decreasing grain size, indicating that the passive film formedon fine grains had a faster dissolution and repair rate. The pitting potential and the width of passive rangeincreased with decreasing grain size. While, the defect density in passive film decreased with increasinggrain size. The passive film formed on aluminum containing fine grains had superior protectionperformance against localized corrosion in general..
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