9110

8448

كارشناسي ارشد

خوردگي و حفاظت از مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مواد

1392

سيزده،70ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

مسعود عطاپور، محمدعلي گلعذار

17/4/93

عبدالمجيد اسلامي، عليرضا علافچيان

مهندسي مواد

ID8448

71The semiconducting properties of passive films formed on AISI 304 in alkaline solutions Ahmad Reza Dorali Beni a dorali@ma iut ac ir Date of Submission Jan 21 2014 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors M Atapour Assistance Professor m atapour@cc iut ac irM A Golozar Emeritus Professor golozar@cc iut ac irAbstractNowadays stainless steel reinforcements appear as an effective solution to increasethe durability of reinforced concrete structures exposed to very aggressiveenvironments AISI 304 stainless steel is widely used as reinforcement in concrete The high corrosion resistance of this type of stainless steel is due to formation of athin film a few nm thickness but highly protective that limits ionic and electronicconductivity The barrier properties of passive film deteriorates and consequentlybreaks down due to presence and diffusion of chloride ions In this work theproperties of passive film formed on AISI 304 stainless steel in 0 2 M NaOH solutionwas investigated In the potential rang of passive film formation growth of thepassive film reduced current density and increased polarization resistance Thepoint defects within the passive film were cation vacancies Therefor the passivefilm was identified as the p type one The electron acceptor density decreased withincreasing the passive film formation potential The thickness of the passive filmwas increased linearly with the film formation potential These observations were ingood agreement with the predictions of the point defect model Also it wasconcluded that the corrosion current density increased and corrosion potentialdecreased by increasing the chloride concentrations The point defect density withinthe passive film increased with increasing the chloride concentration The effect ofimmersion time in the absence and presence of chloride ion was also evaluatedusing EIS technique In chloride containing solutions the impedance parameterswere lower than no chloride solution Also by increasing the chloride content impedance parameters were decreased more quickly Keywords stainless steel passive film electrochemical impedance pittingcorrosion Mott Schottky analyses

مسعود عطاپور، محمدعلي گلعذار

عبدالمجيد اسلامي، عليرضا علافچيان