King Saud University, Saudi Arabia
pp. 269 - 272
Keywords: aluminum alloys, corrosion, EIS, mechanical alloying, polarization, seawater
The as-received metal powders were used to synthesis bulk nanocrystalline Al; Al-10%Cu; and Al-10%Cu-5%Ti alloys using mechanical alloying and high frequency induction heat sintering (HFIHS). The corrosion behavior of these materials in natural Arabian Gulf seawater (AGS) has been investigated using different electrochemical and spectroscopic techniques. The electrochemical impedance spectroscopy measurements showed that the presence of Cu decreases the corrosion of Al and that effect was further reduced when adding Ti. Cyclic potentiodynamic polarization experiments confirmed that adding Cu and Ti decreases the corrosion current and corrosion rate, while increases the polarization resistance for Al in AGS. Potentiostatic current-time indicated that Al suffers both uniform and pitting corrosion, which decrease in the presence of Cu and Ti through decreasing the absolute current that was measured at -0.50 V vs. Ag/AgCl. Scanning electron microscope and energy dispersive X-ray analyses confirmed the decrease of deterioration for Al surface containing Cu and Ti. All measurements were consistent with each other and indicated clearly that the corrosion resistance of these materials in AGS increases in the order Al-10% Cu-5% Ti > Al-10% Cu > Al.