Corrosion Behavior for Al-Cu-Mg Alloy
by Addition of SiO2 Particles in Seawater |
This work involves studying the effect
of adding SiO2 particles on corrosion behavior of Al-Cu-Mg alloy
in 3.5% NaCl solution at room temperature using polarization
method at scan rate 3 mV.sec-1. According to potentiodynamic
polarization test, the results of corrosion rate indicate that
Al-Cu-Mg composites (1, 2, 3 wt% SiO2) gave decreasing in
corrosion rate compared with Al-Cu-Mg alloy due to the covering
the anodic sites for alloy by SiO2 particles and enhancing the
passivity of surface and reducing the dissolution of aluminum.
The cathodic Tafel slope (bc) were decreased after adding SiO2,
while the anodic Tafel slopes (ba) were increased. It is
inferred that the rate of change of current with change of
potential was smaller during anodic polarization than that
during cathodic polarization. Cyclic polarization measurements
were carried out to estimate the pitting resistance of Al-Cu-Mg
composites. The results show that a stable oxide film is formed
during the forward scan on the surface of composites; also the
hystere |
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