Corrosion Behavior of Al-Mg-Zn-Si Alloy Matrix Composites Reinforced with Y2O3 in 3.5% NaCl Solution

The corrosion behavior of the Al-Mg-Zn-Si composite reinforced with Y2O3 particles and the unreinforced Al-Mg-Zn-Si alloy was studied through electrochemical and surface analysis techniques. The samples were manufactured by the Mechanical alloying (MA) technique and were heat treated at 350 degrees C, 400 degrees C and 500 degrees C during 60 min followed by water quenching. The corrosion behavior of the samples was investigated in 3.5 wt.% NaCl by using electrochemical methods such as poteniodynamic polarization curves, linear polarization resistance and electrochemical impedance spectroscopy measurements. In the as-received condition the corrosion resistance for base alloy was lower than the composite, however, when composite was heat treated, its corrosion resistance was higher than that for base alloy, but it was susceptible to localized type of corrosion at the matrix/Y2O3 particles interface.