Document Details

Document Type : Thesis 
Document Title :
STUDY OF SOME N-HETEROCYCLIC QUATERNARY AMMONIUM COMPOUNDS AS POTENCY INHIBITORS FOR STEEL CORROSION IN ACID SOLUTIONS
دراسة بعض مركبات الامونيوم الرباعية ذات حلقة غير متجانسة تحتوي على ذرة النيتروجين كمثبطات فعالة لتآكل الصلب في الوسط الحمضي
 
Subject : Faculty of Sciences 
Document Language : Arabic 
Abstract : The corrosion and inhibitor adsorption processes onto stainless steel/1-X-4[4-(-OCH3)-styryl] pyridinium iodides (X: CH3, C2H5 and C3H7)/hydrochloric acid systems was studied by means of chemical (hydrogen evolution (HE) and weight loss (WL)) measurements and electrochemical (impedance spectroscopy (EIS) and potentiodynamic polarization (PDP)) measurements. Surface morphology of stainless steel before and after immersion in 2.0M HCl without and with the studied inhibitors was studied using scaning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Some factors such as inhibitor concentration, temperature, and immersion time were studied. It was found that the studied inhibitors showed excellent inhibitory behavior for corrosion of stainless steel in 2.0 M HCl. Results show that corrosion rate decreases and inhibition efficiency increases with increasing concentration of inhibitors. PDP measurements indicate that the studied inhibitors act as mixed type that inhibits both anodic dissolusion and cathodic hydrogen evolution. For one and the same concentration, it was found that the inhibition efficiency of the studied inhibitors follows the order: III-C3H7 > II-C2H5 > I-CH3. Some difference in inihibition efficiency between chemical and electrochemical measurement was obtained. This difference in inhibition efficiency values arise from a long-term estimation of corrosion can be achieved in chemical techniques by the short-time consuming electrochemical techniques. The studied inhibitors can form compact adsorption film according to Langmuir adsorption isotherm and the high negative values of indicate strong and spontaneous adsorption of the studied inhibitors onto stainless steel surface.The effect of temperature (30-60oC) shows good pickling inhibitors qualities as the studies inhibitors keep their protective properties even at relatively high temperature (60◦C). On the bases of thermodynamic parameters, comprehensive adsorption (physisorption and chemisorption) for the studied inhibitors on stainless steel surface was suggested. Evidence of the formation of the adsorbed layer was confirmed from SEM and EDX. Quantum chemical approach was applied in order to get a better understanding about the relationship between the inhibition efficiency and molecular structure of the studied inhibitors and the calculated quantum chemical parameters were discussed. The data showed that the inhibition efficiency of the studied inhibitors increases with increasing immersion time (5, 30, 60 and 90 min) in the tested solution and this result implied that the studied inhibitors have a long-term effect as potent inhibitors. 
Supervisor : Dr. Aisha H. Moubaraki 
Thesis Type : Master Thesis 
Publishing Year : 1439 AH
2018 AD 
Added Date : Thursday, July 5, 2018 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
هناء سعد عواجيAwaji, Hana SaadResearcherMaster 

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