مهدیس نوری - دانشکده فنی و مهندسی
دانشكده فني مهندسي
گروه مهندسي مواد
جلسه دفاعیه پایان نامه جهت دريافت درجه كارشناسي ارشد در رشته مهندسي مواد
گرايش شناسایی و انتخاب مواد
عنوان:
مطالعه مکانیزم خوردگی و بازدارندگی از خوردگی فولاد کربنی در محلولهای حاوی HCl و H2S
استاد راهنما:
دكتر آرش فتاح الحسینی
داوران:
دکتر شیخی
دکتر اصفهانی
نگارش:
مهدیس نوری
زمان: سه شنبه 24 آذر ماه 94 ، ساعت 30/15
مکان: کلاس 10
چكيده: |
واژههای کلیدی: بازدارنده های خوردگی، فولاد کربنی، امپدانس الکتروشیمیایی، پلاریزاسیون تافل
Abstract: Nowadays, corrosion is one of the main problems for the petroleum industry, that using from corrosion inhibitors is one of the best ways to prevent or control the rate of corrosion in various units of this industry. Cheapness, availability and having renewable resources are reasons for using of plant extracts as corrosion inhibitor which has been the attention of many researchers for several decades. There are various compounds, such as alkaloids, flavonoids, tannins and amino acids in plant extracts. In the molecular structure of most of these compounds there are long-chain hydrocarbon, aromatic rings and hetroatoms such as oxygen and nitrogen, which have lone pair electrons, which cause more adsorbtion of inhibitor on the surface and reduce the rate of corrosion. In this study, the inhibition behavior of Lemon verbena, Calendula officinalis, Salvia officinalis, Urtica dioica, Henna, Cascuta and Foeniculum vulgare plant extracts on carbon steel corrosion in solutions containing Hydrogen sulfide and Hydrochloric acid, for the first time, were examined. For this purpose, electrochemical tests such as Tafel polarization and electrochemical impedance spectroscopy were used. Tafel polarization test results showed that all inhibitors which used act as mixed type inhibitor. Aslo was observed that corrosion current density decreased and percentage of inhibition increased with increasing concentration of inhibitors. The electrochemical impedance test results showed that, the diameter of the semicircles of Nyquist plots increased and electric double layer capacitance decreased with increasing inhibitors concentrations. This matter is shown more absorption of inhibitor on the metal surface which cause increasing protection efficiency. It was found from isotherm Studies that all of them adsorbed on the steel surface physically which obey from langmuir isotherm Key Words: corrosion Inhibitor, carbon steel, electrochemical impedance, tafel polarization
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