الفهرس 
Published paperOnly 14 pages are availabe for public view
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Abstract
The purpose of the present investigation is to study the corrosion and corrosion inhibition of X-65 type carbon steel in oil wells formation water in absence and presence of the prepared surfactants with different number of ethylene oxide units (S-5, 10,20 and 30)and cationic surfactants. Different techniques potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) are used. Is devoted to the results and discussion as shown: 1- Structural confirmation: The structures of the prepared compounds (before and after ethoxylation) were confirmed through spectrophotometric techniques (FTIR & 1HNMR). 2- Surface active properties: Some surface active properties of the prepared ethoxylated imidazole derivatives were investigated through surface tension measurements of their aqueous solutions such as (CMC, γCMC, ГMax, πCMC ) and the thermodynamic parameters (∆Gads, ∆Gmic )were investigated also , from the data we conclude that the prepared surface active materials can be used as a corrosion inhibitors. 3- Electrochemical corrosion properties : The effect of the prepared non-ionic surfactants of different number of ethylene oxide units (S-5, 10, 20 and 30) and cationic surfactants are examined as a corrosion inhibitors on the rate of corrosion X-65 type carbon steel in oil wells formation water using the previous different techniques: I) Open Circuit Potential Measurements (OCP) The variation of the OCP of the carbon steel electrode as a function of the period of exposure in the absence and presence of various concentrations of the surfactants were measured against a saturated calomel electrode (SCE). It was found that the potential of carbon steel electrode immersed in formation water tends toward more negative potential firstly, giving rise to short step. By addition of inhibitor molecules to the aggressive medium produces a slightly positive shift in Ecorr due to the formation of a protective film on the carbon steel surface.
II) Potentiodynamic Polarization Measurements
Using the potentiodynamic polarization technique, the kinetic parameters determined (Icorr, Ecorr, and ɳ %) show that these surfactant are of the mixed type adsorption inhibitors, and the inhibition efficiency increases with increasing inhibitor concentrations, polarization resistance, surface coverage, and decreasing the corrosion current density.
III) Electrochemical Impedance Spectroscopy Measurements (EIS)
The results obtained from (EIS) show that the corrosion reactions in the absence and presence of the prepared compounds proceed under charge transfer control. The results determined (Rct, Cdl, and ɳ %) show that the presence of surfactants lead to increase Rct and decrease the electrical double layer capacitance due to the gradually replacement of water molecules and other aggressive anions by the adsorption of inhibitor molecules on the metal surface forming an adherent film on the metal surface i.e. increasing the surface coverage and subsequently increasing the inhibition efficiency.
EIS data confirm the inhibition behavior of the prepared surfactants obtained using other techniques.
4- Scanning Electron Microscopy (SEM)
The SEM results, indicated that the carbon steel sample placed in the oil wells formation water for 60 days in the absence of inhibitor show highly damage to the surface, while the sample placed in the solution in the presence of 250 ppm of the inhibitor did not significantly affected as a result of the inhibitor layer formed on the carbon steel surface.
5- Energy Dispersive Analysis of X-Rays (EDX)
The results of EDX, reveal that the curve of iron atom (Fe) in the presence of 250 ppm of the inhibitor (12) less than in the absence of the inhibitor, which indicates that the surfactant inhibitor layer formed on are strongly attached to the carbon steel surface, and thus leads to a high degree of inhibition efficiency.
At the end of the thesis, the relation between the surface properties of the investigated surfactants and their corrosion inhibition efficiency ɳ % were studied.