| Titre : | Green corrosion inhibition of carbon steel in acid medium using leaves extract of Moringa oleifera |
| Auteurs : | Fatma zohra LACHHEB, Auteur ; Kamal Djail, Directeur de thèse |
| Editeur : | Biskra [Algérie] : Faculté des Sciences Exactes et des Sciences de la Nature et de la Vie, Université Mohamed Khider, 2024 |
| Format : | 1 vol. (59 p.) / ill., couv. ill. en coul / 30 cm |
| Langues: | Anglais |
| Langues originales: | Anglais |
| Mots-clés: | Steel corrosion, Green inhibitor, Gravimetric method, Electrochemical method |
| Résumé : |
Through this work, we aim to study the corrosion of X70 steel in acidic medium HCl, and to study the inhibitory effect of steel corrosion using Moringa oleifera leaf extracts . We initially conducted a chemical examination to determine the most important active elements present in the plant extract, and the results obtained confirmed that the plant extracts have a good effect against the corrosion of steel. We found, using the gravimetric method, that the inhibitory efficiency increases with increasing inhibitor concentration and reaches a maximum value of 82.96% at a concentration of 3.10-3 g/L . We also achieved similar results using electrochemical methods (polarization and electrochemical impedance), where the inhibitory efficiency was 82.96% and 92.33%, respectively . |
| Sommaire : |
General Introduction .....01 Theoretical part Chapter One : Metal corrosion and I. Generality on the Corrosion of metals .........05 I.1. Historical .........05 I.2. Definition of steel ................05 I.3. Classification of steel ............05 I.3.1. Classification according to their chemical composition ..............06 I.3.2. Classification by instructions for use .......06 I.4. Definition of Corrosion ...........07 I.5. Corrosion Types............ 07 I.5.1. Chemical Corrosion .......08 I.5.2. Electrochemistry Corrosion ........08 I.5.3. Biochemistry Corrosion ............08 I.5.4. Accompanied by wear Corrosion ....08 I.6. corrosion forms ................08 I.6.1. Uniform corrosion ............08 I.6.2. Galvanic corrosion ...........09 I.6.3. Pitting corrosion ............09 I.6.4. Stress corrosion cracking ....10 I.6.5. Corrosion fatigue ............10 I.6.6. Ntergranular corrosion .......10 I.6.7. Crevice Corrosion ............11 I.6.8. Filiform corrosion ...........11 I.6.9. Erosion corrosion ............12 I.6.10.Fretting corrosion ...........12 I.7. Factors Affecting Corrosion ....12 I.7.1. Environmental Factors ........12 I.7.2. Metallurgical Factors ........12 I.7.3. Mechanical Factors ...........12 I.8. Corrosion as a Chemical Reaction ............13 I.8.1. Corrosion in Acids ............13 I.8.2. Corrosion in natural and alkaline solution .............13 II. Corrosion inhibitors ..............14 II.1. Historic .........4 II.2. Definition of inhibition ........14 II.3. Classification of Corrosion Inhibitors .........15 II.3.1. Depending on the nature of the chemical ......15 II.3.1.1. Organic inhibitors ................16 II.3.1.2. Inorganic inhibitors ..............16 II.3.2. Depending on the electrochemical nature of the process ......17 II.3.2.1. Anodic inhibitors ....17 II.3.2.2. cathodic inhibitors ..17 II.3.2.3. Mixed inhibitors .....17 III. Methods of corrosion evaluation .........18 III.1. Gravimetry method ..........18 III.2.Electrochemical method ............18 III.2.1. Stationary method: polariza ves .........18 III.2.2. Transient method: electrochemical impedance spectroscopy .............19 Chapter Two : General information of moringa oleifera Introduction ............21 I. General information of moringa oleifera .....21 I.1. Definition ...........21 I.2. Geographical distribution ...........21 I.3. Systematic classification of the plant .......22 I.4. Botanical description of the plant M. oleifera ..........23 I.5. medicinal properties of moringa ..................25 II. Phytochemical study ......26 II.1.1. Alkaloids ...........26 II.1.2. Flavonoids ..........27 II.1.3. Tannins .............28 II.1.4. Saponins ............28 II.1.5. Anthocyanins ........28 II.1.6. Glucosides ..........29 II.2. Extraction methods ....29 II.2.1. Definitions .........29 II.2.2. Types d’extraction ..30 II.2.3. Solvent extraction ..30 II.2.3.1. Maceration ........30 II.2.3.2. Soxhlet ...........31 II.2.3.3. Hydrodistillation .............32 Experimental part Chapter Three : Materials and methods I. Phytochemical evaluating for the plant .............35 I.1. Sample preparation ...............................35 I.2. Chemical composition of Moringa oleifera .........35 I.2.1. Alkaloid Test ....................35 I.2.2. Test of Flavonoids ...............36 I.2.3. Test for Tannins .................37 I.2.4. Test for Saponins ................37 I.2.5. Test for Unsaturated Sterols and Terpenes .............38 I.2.6. Test for anthocyanins ................38 I.2.7. Test for leucoanthocyanins ...........39 I.2.8. Starch Test ........39 I.2.9. Test for Glucosides ...............40 I.3. Green inhibitors use ................40 I.3.1. Preparation of the inhibitor ......40 II. Gravimetric study of corrosion inhibition ..........41 II.1.Studied Material ..............41 II.1.1. Characteristics of X70 Steel ...........42 II.1.2. Chemical properties .........42 II.2. Sample preparation ............42 II.2.1. Cutting ................42 II.2.2. Polishing ..............43 II.2.3. Preparation of corrosive environments ...........43 II.3. Testing techniques (gravimetric study) ............44 II.3.1. Experimental apparatus ...........44 III. Electrochemical Study ...............45 III.1. Electrochemical Setup .............45 III.2. Electrochemical Cell ..............46 Chapter Four : Results and discussions I. Phytochemical screening .......................... 48 II. Gravimetric study ..........51 II.1. Microscopic observation of steel ...............51 II.2. Effect of inhibitor concentration in 7 days of immersion ............52 III. Electrochemical method ..................54 III.1. Free potential measurement ............54 III.3. Electrochemical impedance curves ...............55 III.4. A Comparative study of the influence of the inhibitor concentration on the three analysis methods ...........57 General conclusion ....59 Reference Abstract |
| Type de document : | Mémoire master |
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| MCH/625 | Mémoire master | bibliothèque sciences exactes | Consultable |
