ThermodynamicProperties of Nicotinicacid in Dilute HCl and inaqueous NaCl solutions at (293.15, 298.15, 303.15 and 308.15)K

Apparent molar volume, V?, and viscosity B-coefficient of nicotinc acid in water and in aqueous NaCl solutions have been determined from density and viscosity measurements at (293.15, 298.15, 303.15 and 308.15) K. The experimental density data were evaluated by Masson equation, and the derived, apparent molar volume at infinite dilution, Vo?, and the slope Sv, were interpreted in term of solute-solvent and solute- solute interactions. Transfer apparent molar volumes at infinite dilution of nicotinic acid from water to NaCl solutions at various temperatures have been calculated.The viscosity data have been analyzed using Jones-Dole equation, and the derived parameters, Jones-Dolecoefficient, B,and Falkenhagen coefficient,A, have been also interpreted in terms of solute-solvent and solute-solute interactions respectively. The variation of B coefficient with temperature, (dB/dT), was also determined, the negative values indicate that nicotinic acid in aqueous NaCl solution is structure making. The results were interpreted in terms of complex vitamin-water-co-solute (NaCl) interactions. The free energy, enthalpy, andentropy of activation were calculated using the Nightingale, Benck, and Eyring equations. Free energies of activation of viscous flow ( *1) per mole, and, ( *2) per mole,of solvent and solute, respectively, were also calculated. The effects of soluteson the structure of water were interpreted in terms of viscositiesand the thermodynamic parameters

Corrosion, Passivity and Pitting of Inconel (600) in Sulphuric Acid

A potentiostatic study of the behaviour of Inconel (600) in molar sulphuric acid has been carried out over the temperature range 293-313 K. Values have been established for the potentials and current densities of the corrosion, active-passive transition, passivity and transpassive states. For corrosion, the current density (ic) and potential (Ec) have been determined from well-defined Tafel lines. The potential and current density prior to the commencement of passivity have been obtained corresponding respectively to the critical potential (Ecr( and to the current density (icr) for the active-passive transition state. The passive range was defined by the respective potentials and current densities for passive film formation and dissolution. The dissolution point was correlated with transpassive potential (Et) and current density (it). All the estimated potentials and current densities for the various states were influenced by temperature and the presence of additives in the sulphuric acid. Additives such as nitric acid, thiourea and sodium chloride lowered the corrosion current density (ic) of the alloy while hydrochloric acid enhanced the value of ic. Addition of thiourea or sodium chloride or hydrochloric acid caused a shift in the corrosion potential (Ec) to less negative values while nitric acid shifted Ec to more negative potentials. The kinetic effect of the additives have been studies. Values of activation energy (E) were considered to be apparent and some negative values of E have been obtained with certain additives for the critical and passivity processes. Such negative E values were attributed to small values of true energies of activation together with relatively large exothermic enthalpies of such processes

Corrosion Inhibition Efficiency Investigation of Yttrium Oxide Nanoparticles Coated on Carbon Steel Alloy

               تظهر الجسيمات النانوية لأكسيد المعادن تفردًا في التطبيقات التقنية المختلفة نظرًا لخصائصها الفيزوكيميائية المناسبة. على وجه الخصوص ، فإن الجسيمات النانوية لأكسيد الإيتريوم (Y2O3NPs) مألوفة للتطبيقات التقنية بسبب ثابت العزل الكهربائي العالي  وثباتها الحراري. يستخدم على نطاق واسع كمواد مضيفة لمجموعة متنوعة من المنشطات الأرضية النادرة ، والتصوير البيولوجي ، والعلاجات الضوئية. في هذه الدراسة تم اختيار جزيئات أوكسيد الإيتريوم النانوية (Y2O3NPs) كمثبط صديق للبيئة. تم التحقيق في التوصيف الفيزيائي والكيميائي لـجزيئات أوكسيد الإيتريوم النانوية بواسطة مطيافية الاشعة تحت الحمراء (FT-IR) ، والتحليل الطيفي للأشعة فوق البنفسجية ، وانحراف الأشعة السينية (XRD) ، والفحص المجهري الإلكتروني (SEM) وطيف الأشعة السينية المشتتة للطاقة (EDX). يُظهر طيف FT-IR الذروة المميزة الرئيسية لـ YOY عند 565 cm-1 مما يشير إلى تكوين جزيئات أوكسيد الإيتريوم النانوية. كشف نمط XRD عن تشكيل هيكل مكعب أحادي الطور من YONPs. لوحظ التشكل السطحي بواسطة المجهر الالكتروني الماسح  و أظهرت نتيجة طيف الاشعة السينية المشتتة  أن تركيبة الإيتريوم والأكسجين في YONPs كانت 78.74% و 21.62% على التوالي. تم استخدام تقنية الترسيب الكهربائي لتراكيز مختلفة,0.15  0.26 و0.3 عياري  من جزيئات أوكسيد الإيتريوم النانوية كطلاء على سطح الفولاذ الكربوني وتم فحص السلوك المضاد للتآكل من خلال منحنى الاستقطاب في 18.204% محلول كلوريد الكالسيوم عند خمس درجات حراريه في المدى   293 –  313 كلفن. تشير النتائج التي تم الحصول عليها على ان جزيئات Y2O3NPs شكلت طبقة واقية تعمل كحاجز لحماية سبيكة الصلب الكربوني. بالإضافة الى ذلك,  وجد أن طلاء بتركيز 0.26 عياري من جزيئات أوكسيد الإيتريوم النانوية أظهر كفاءة أفضل في الحماية من التآكل بالمقارنة مع طلاء بتراكيز  0.15 و 0.37 عياري ، على التوالي.Metal oxide nanoparticles demonstrate uniqueness in various technical applications due to their suitable physiochemical properties. In particular, yttrium oxide nanoparticle(Y2O3NPs) is familiar for technical applications because of its higher dielectric constant and thermal stability. It is widely used as a host material for a variety of rare-earth dopants, biological imaging, and photodynamic therapies. In this investigation, yttrium oxide nanoparticles (Y2O3NPs) was used as an ecofriendly corrosion inhibitor through the use of scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), UV-Visible spectroscopy, X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy(EDX), the physico-chemical characterization of Y2O3NPs was examined. The primary characteristic peak of YOY at 565 cm-1, which indicates the synthesis of nanoparticles, is seen in the FT-IR spectra. The XRD pattern showed that a single phase cubic structure of YONPs with an Ia-3 space group had formed. SEM was used to examine the surface morphology. The composition of Yttrium and oxygen in Y2O3NPs was determined to be 78.74% and 21.26%, respectively, according to the EDX results. The anticorrosive behavior was tested by polarization curve in 18.204% CaCl2 solution at five temperatures in the range 293- 313 K. Various concentrations 0.15 0.26 and 0.37 of N Y2O3NPs coating on the carbon steel surface were applied using the electrophoresis deposition method. The obtained results indicated that Y2O3NPs formed a protective film acts as a physical barrier for the protection of steel alloy. Additionally, corrosion protection efficiency values of 0.26 N Y2O3NPs coating were superior to that of 0.15 and 0.37 N Y2O3NPs coating, respectively

Inhibition Effect of Hydrazine-Derived Coumarin on a Mild Steel Surface in Hydrochloric acid

In this work, economy novel hydrazine-derived coumarin 4-(6-methylcoumarin)acetohydrazide (MCA) were synthesized, characterized, and tested as an inhibitor for the corrosion of a surface of mild steel in an acidic environment through weight loss and Scanning electron microscopy (SEM) techniques. Results showed that the synthesized inhibitor can inhibit the corrosion of mild steel surface in a 1 M hydrochloric acid environment. The corrosion inhibition efficiency of MCA increases with increasing MCA concentration and decreases with increasing temperature. SEM analysis showed the formation of a film as a protective layer from MCA molecules on the surface of mild steel. Adsorption of the MCA molecules on the mild steel surface in the presence of hydrochloric acid environment was obeyed Langmuir isotherm. The density functional theory (DFT) calculations were used to study the relationship between molecular structure and inhibition efficiency and they found in good agreement

Experimental studies on inhibition of mild steel corrosion by novel synthesized inhibitor complemented with quantum chemical calculations

One of best method, which was used to prevent the mild steel from corrosion, was through employed natural or synthetic organic chemical compounds. Here in, we displayed a Schiff base derivative which has nitrogen, oxygen and sulfur atoms as corrosion inhibitor for MS “mild steel” in 1 M HCl “hydrochloric acid” solution. Synthesized inhibitor was characterized by using of FT-IR “Fourier transform infrared” and NMR “Nuclear magnetic resonance” spectroscopies in addition to CHN analysis technique. The weight loss and SEM “Scanning electron microscope” studies showed that inhibitor have the ability to prevent the alloy surface from corrosive solution by adsorbing on MS surface to form stable adsorbed layer that results in the higher inhibition efficiency. The inhibition influence of the synthesized inhibitor was increased parallel with increasing concentration and decrease with rising temperature degrees. Furthermore, DFT “Density function theory” has been employed to calculate quantum chemical parameters “Energy, highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and electronegativity (χ)” which performed on synthesized corrosion inhibitor to determine the relationship between the structure of synthesized inhibitor molecule and inhibition performance. Keywords: Corrosion, Inhibitor, Mild steel, FT-I

Experimental and quantum chemical simulations on the corrosion inhibition of mild steel by 3-((5-(3,5-dinitrophenyl)-1,3,4-thiadiazol-2-yl)imino)indolin-2-one

Iraq has been one of the most extensive oil and natural gas industries in the world. The corrosion of mild steel is costly and insufficiency process. It is responsible for great loss in manufacture and environment. Natural and organic inhibitors have been utilized for a long time to inhibit the corrosion. Selected thiadiazol derivative, namely 3-((5-(3,5-dinitrophenyl)-1,3,4-thiadiazol-2-yl)imino)indolin-2-one (TDIO) was investigated for it inhibitive impacts in 1 M HCl medium on corrosion of mild steel using weight loss and scanning electron microscope techniques. The maximum inhibition efficiency up to 90.7% at the maximum inhibitor concentration 0.5 mM. Surface morphology of results demonstrated that TDIO formed adsorbed film on surface of mild steel in hydrochloric acid solution. Give molecular based clarifications to the inhibitive impacts of the studied. The interactions between mild steel surface and the inhibitor molecules have been undertaken to further corroborate the methodological results. Keywords: Dinitrophenyl, Indolin, Morphology, Corrosion inhibito