الفهرس 
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Abstract
In this work the electrochemical corrosion behavior of Fe, and
Fe-binary and ternary alloys, namely, Fe-12Al, Fe-19Al, Fe-28Al and
Fe-Al-Ti, was investigated in acidic, neutral and alkaline solutions. The
effects of Ti and xAl (X=12, 19 and 28 wt.%) alloying elements on the
electrochemical corrosion behaviour of iron-based alloys in aqueous
solutions of different pH were also investigated. The electrochemical
corrosion and passivation behaviors of the different Fe-alloys were
studied in alkaline solutions of the highest corrosion rates containing
different amino acids. Conventional electrochemical techniques such as
open-circuit potential measurements, OCP, potentiodynamic
polarization (PDP) methods and electrochemical impedance
spectroscopy (EIS) were used. The surface morphology and
constituents of the surface components were analyzed by SEM/EDAX
analysis. The electrochemical measurements clearly confirmed that, the
corrosion resistance reaches maximum passivation in neutral rather
than alkaline or acidic solution; moreover, the alkaline solution
recorded the highest corrosion rates for all investigated alloys. The
presence of alloying elements improves the corrosion resistance of Fe-
binary and ternary alloys in the different aqueous solutions. The
increased Al content in the binary Fe-xAl alloys increases the corrosion
resistance; moreover, ternary Fe-Al-Ti is superior to binary Fe-xAl
alloys against corrosion in all tested media. In alkaline solutions
containing different amino acids the results showed that the promising
amino acids which give the highest inhibition efficiency are threonine,
lysine, cystine, arginine and tyrosine. Also the calculated values for the
adsorption of tyrosine on the surface of the alloys indicate that the
adsorption process is of physical nature, and there is no chemical
interaction between the inhibitor molecules and the electrode surface.
The impedance data were fitted to the equivalent circuit models that
explain the different electrochemical processes occurring at the
electrode/electrolyte interface.