الفهرس 
Introduction and Literature ReviewOnly 14 pages are availabe for public view
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Abstract
In this work the electrochemical behavior of carbon steel
was investigated in saline acidic, neutral and basic solutions.
Conventional electrochemical techniques such as open-circuit
potential measurements, polarization methods and electrochemical
impedance spectroscopy (EIS) were used. Scanning electron
microscope (SEM) was used to study the surface of carbon steel
sample. The results have shown that the rate of corrosion in acidic
solution is relatively high compared to that in neutral or basic
solutions. The increase in chloride ion concentration and sulphate
nearly lead to increase the corrosion rate. The impedance data were
fitted to an equivalent circuit model that explains that different
electrochemical processes occurring at the electrode/electrolyte
interface.
Also, the inhibition of corrosion of carbon steel in neutral
solutions by using β-carotene and Thiourea, as environmentally
safe corrosion inhibitors, was investigated. The calculated free
energy of adsorption reveals that adsorption of β-carotene, β-cart.,
and Thiourea, TU, on the carbon steel alloy is of a physical nature,
and there is no chemical interaction between the inhibitor
molecules and the metallic surface.
SEM image of carbon steel after immersion for 120 min in
3.5 % NaCl and in 0.6 M Na2SO4 solution revealing severe damage
on the surface caused by metal dissolution, but proves that the steel
surface was protected after adding 50 mg/L β-carotene inhibitor. It
is observed that the surface damage has diminished compared with
the blank solution