Corrosion Behavior of Ψ and β Quasicrystalline Al-Cu-Fe Alloy

Two nanostructured Al-Cu-Fe alloys, Al64Cu24Fe12 and Al62.5Cu25.2Fe12.3, have been studied. Icosahedral quasicrystalline (psi) Al64Cu24Fe12 and crystalline cubic (beta) Al62.5Cu25.2Fe12.3 cylindrical ingots were first produced using normal casting techniques. High-energy mechanical milling was then conducted to obtain psi icosahedral and beta intermetallic nanostructured powders. Electrochemical impedance spectroscopy, linear polarization resistance, and potentiodynamic polarization were used to investigate the electrochemical corrosion characteristics of the powders in solutions with different pH values. Current density (i(corr)), polarization resistance (R-p), and impedance modulus (vertical bar Z vertical bar) were determined. The results showed that regardless of pH value, increasing the solution temperature enhanced the corrosion resistance of the both phases. However, the electrochemical behavior of the psi phase indicated that its stability depends on the submerged exposure time in neutral and alkaline environments. This behavior was related to the type of corrosion products present on the surfaces of the particles along with the diffusion and charge-transfer mechanisms of the corrosion process.