Essam Khamis - Academia.edu (original) (raw)

Papers by Essam Khamis

Materials and Corrosion/Werkstoffe und Korrosion, 1993

Corrosion of amorphous 76Ni-24P alloy 461 Effect of surfactants on the corrosion of amorpho,us 76... more Corrosion of amorphous 76Ni-24P alloy 461 Effect of surfactants on the corrosion of amorpho,us 76Ni-24P alloy in neutral solutions EinfluB von oberflachenaktiven Stoffen auf die Korrosion der amorphen Legierung 76Ni-24P in neutralen Losungen N. G. Gomaa'), E. Khamis2), A. Ahmed2) and S. Abaza') 76Ni-24P amorphous alloys have been electrodeposited from solutions containing sodium lauryl sulphate (SLS) and triton-X 100 (TX-100) to improve the surface quality of the specimens. Corrosion behaviour of electrodeposited amorphous alloys in sulphate and chloride solutions at 2.5 "C has been studied by potential-time decay, linear polarization resistance and potentiodynamic techniques. Anodic polarization curves show that the specimens exhibit mild passivity at potentials between approximately-200 mV and 200 mV (SCE) and dissolve transpassively above 200 mV (SCE). The sulphate solution was found to increase the dissolution of the samples treated by the surfactants during the substrate brass plating. The nonanionic surfactant increases the corrosion current by 10 times compared to the anionic one which enhances the current by 400 times; the interpretation was based on the enhanced dissolution of the microcrystals of the specimens in the sulphate solution and to the steric hindrance of the surfactants. In addition, the alloys are more resistant to chlorides due to the formation of a phosphatelhypophosphite film which protects the surface from dissolution. Die Legierung 76Ni-24P wurde elektrolytisch aus Losungen abgeschieden, die zur Verbesserung der Oberflachenqualitat Natriumlaurylsulfat (SLS) und Triton-X 100 (TX-100) enthielten. Das Korrosionsverhalten dieser amorphen Legierungen wurde in Sulfat-und Chloridlosungen bei 2.5 "C untersucht, und zwar mittels Potential-Zeit-Verhalten, linearem Polarisationswiderstand und potentiodynamischen Methoden. Die anodischen Polarisationskurven zeigen, dal3 die Legierung bei Potentialen zwischen etwa-200 und 200mV (SCE) eine gewisse Passivitat erreicht und oberhalb 200mV (SCE) transpassiv in Losung geht. In der Sulfatlosung ist die Auflosung der Nip-Legierung verstarkt, bei deren Abscheidung auf Messing oberflachenaktive Stoffe anwesend waren. Nichtanionische oberflachenaktive Stoffe erhohen dabei den Korrosionsstrom um den Faktor 10, anionische hingegen urn den Faktor 400. Zur Erklarung wird angenommen, daR in der Sulfatlosung bevorzugt die Mikrokristalle gelost werden; eine Rolle spielt auch die sterische Behinderung der oberflachenaktiven Stoffe. In Chloridlosung sind die Legierungen bestandiger, da dann ein Phosphat/Hypophosphit-Film entsteht, der die Auflosung der Oberflache verhindert.

Materialwissenschaft und Werkstofftechnik, 1996

Potentiodynamic polarization and cyclic voltametry measurements were employed to study the effect... more Potentiodynamic polarization and cyclic voltametry measurements were employed to study the effect of topical fluoride preparations on corrosion of silver amalgam alloy in synthetic saliva and aqueous fluoride solutions. Results support that small amounts of copper and indium alloyed to silvertin amalgam enhance corrosion resistance considerably. lndiloy shifts both the open circuit potential and the anodic polarization curve to more positive potential values, this lead to a decreases in the current density.The weak activity of Indiloy as compared with Spheraloy is attributed to the fact that the amount of y2 phase (tinmercury) present in the former is much lesser than that present in the latter. Findings also show that fluoride solutions (NaF, SnF and SnF + HCI) enhance the dissolution rate of the investigasted alloys and the polarization curves illustrate the appearance of an activepassive transitions. This behaviour was discussed on the basis of complex formation. Cyclic voltammograms confirm the results obtained from the potentiodynamic polarization measurements and elucidate the anodic oxidation peaks of silver oxide and copper verifying the proposed mechanism.

British Corrosion Journal, 2000

... The inhibitor AK IBRAHIM acts by covering the cathodic area of the metal surface through adso... more ... The inhibitor AK IBRAHIM acts by covering the cathodic area of the metal surface through adsorption of the phosphorus atom. A synergistic eVect has been observed for KBr, KI, and KSCN with vinyl triphenyl phosphonium bromide. ...

Chemical Industry and Chemical Engineering Quarterly, 2017

The corrosion protection and antifouling properties of varnish-coated steel panels containing dif... more The corrosion protection and antifouling properties of varnish-coated steel panels containing different amounts of cannabis extracts were investigated using electrochemical impedance spectroscopy (EIS), salt spray and immersion tests in 0.5 M NaCl solution and subjected to a field test in seawater. Analysis of the experimental data showed that the presence of cannabis extract resisted the deterioration (peeling off) tendency of the varnish-coated steel panels exposed to aggressive environments. Visual inspection showed that the cannabis extract also provided good antifouling properties.

Desalination and Water Treatment, 2016

AbstractScale deposition and corrosion have become a nightmare for any oil and gas operations. Th... more AbstractScale deposition and corrosion have become a nightmare for any oil and gas operations. The antiscalant properties of the green algal (Ulva compressa) and the red algal (Pterocladiella capillacea) extracts were studied using conductivity, electrochemical impedance spectroscopy (EIS), and chronoamperometry techniques in conjunction with microscopic and infrared examinations. The corrosion inhibitive characteristics were investigated using EIS and potentiodynamic polarization measurements. Mineral scales were deposited from the brine solution by cathodic polarization of the steel surface at −0.9 V (vs. SCE). Potentiodynamic polarization curves indicated that the green algal (U. compressa) and the red algal (P. capillacea) extracts inhibit the corrosion of steel by controlling the cathodic oxygen reduction process.

Materialwissenschaft und Werkstofftechnik

Corrosion inhibition of steel in sulphuric acid by six different herb plants has been studied usi... more Corrosion inhibition of steel in sulphuric acid by six different herb plants has been studied using a.c and d.c electrochemical techniques. The environmentally friendly investigated compounds are namely: thyme, coriander, hibiscus, anis, black cumin and Garden cress. Electrochemical impedance spectroscopy has been successfully used to evaluate the performance of these compounds. The ac measurements showed that the dissolution process is activation controlled. Bode and theta diagrams show only one time constant (s). Potentiodynamic polarization curves indicate that the studied compounds are mixed-type inhibitors. The order of increasing inhibition efficiency was correlated with the change of the constituent active materials of the compounds. Thyme, which contains the powerful antiseptic thymol as the active ingredient, offers excellent protection for steel surface.

International journal of electrochemical science

The inhibitive efficiency of 6-methyl-2-thioxopyrimidinone (MTP), 6-phenyl-2-thioxopyrimidin-4one... more The inhibitive efficiency of 6-methyl-2-thioxopyrimidinone (MTP), 6-phenyl-2-thioxopyrimidin-4one (PhTP) and 5-cyano-6-phenyl-2-thioxopyrimidin-4-one (CPhTP) for brass corrosion in 0.1 M H 2 SO 4 at 30 0 C were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. These compounds inhibit the corrosion of brass even at very low concentrations and the order of increasing the inhibition efficiency was correlated with the modification of the molecular structure of the inhibitors. The anodic polarization curves of brass in 0.1 M H 2 SO 4 in presence of higher concentrations of PhTP showed a passivity and limiting current behavior indicating the formation of [Cu(PhTP)] + sparingly soluble complex. Theoretical fitting of the kinetic-thermodynamic model of the adsorption of inhibitors at the metal surface are tested to clarify the nature of adsorption. Calculation of the activation parameters of the corrosion reaction of copper in absence and presence of the inhibitors indicated that the presence of the cyano group in CPhTP compound favors chemical adsorption of the inhibitor at the metal suface.

Opportunities and Challenges, 2011

ABSTRACT IntroductionAdsorption Mechanisms in Corrosion InhibitionHybrid CoatingsModeling Aspects... more ABSTRACT IntroductionAdsorption Mechanisms in Corrosion InhibitionHybrid CoatingsModeling AspectsGreen InhibitorsConclusions AcknowledgmentsReferences

Transactions of the Korean Society of Mechanical Engineers A, 2009

The protection for copper tarnish was developed by surface treatment method and volatile corrosio... more The protection for copper tarnish was developed by surface treatment method and volatile corrosion inhibiting (VCI) technology. The performance of surface treatment and VCI material is also examined in simulated test environment. Benzotriazole (BTAH) solution that contained molybdate showed best performance than others. Usage of VCI materials with surface treatment was more effective. The protection film foamed on the surface of copper was investigated by auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). Molybdate does not participate in the formation of the protective film but promotes the passivation effect. This facilitates the stabilization of the cuprous oxide film, and strengthens the adsorption of BTAH.

Advances in Chemistry, 2014

Lead adsorption by green Enteromorpha algae was studied. Adsorption capacity was 83.8 mg/g at pH ... more Lead adsorption by green Enteromorpha algae was studied. Adsorption capacity was 83.8 mg/g at pH 3.0 with algae (E) and 1433.5 mg/g for silicates modified algae (EM). FTIR and thermal analysis of algae materials were studied. Thomas and Yoon-Nelson column model were best for adsorbent (E) and algae after reflux (ER) and Yan model for (EM) with capacity 76.2, 71.1, and 982.5 mg/g, respectively. (ER) and (EM) show less swelling and better flow rate control than (E). Nonlinear methods are more appropriate technique. Error function calculations proved valuable for predicting the best adsorption isotherms, kinetics, and column models.

Journal of Applied Electrochemistry - J APPL ELECTROCHEM, 2002

The corrosion inhibition of steel in water from Western Desert (Egypt) crude oil by nine S-alkyl ... more The corrosion inhibition of steel in water from Western Desert (Egypt) crude oil by nine S-alkyl isothioronium halides was studied using open-circuit potential (OCP) measurements and potentiodynamic polarization tests. The objectives were to determine (a) the effect of chain length of the alkyl groups on the inhibition efficiency, (b) the effect of halide counter ion on the performance of the inhibitor, and (c) to apply a recent developed kinetic-thermodynamic model on the data and compare it with common adsorption isotherms. The number of active sites, binding constant and change of free energy of adsorption were computed for all inhibitors studied. The inhibition efficiency was correlated with the molecular structure of the inhibitors. It was found that each organic molecule replaces more than one adsorbed water molecule from the steel surface. Potentiodynamic polarization curves indicated that the compounds acted as mixed-type inhibitors. The OCP measurements showed that adsorpti...

Surface and Coatings Technology, 1986

Selected substituted thiosemicarbazides and thiosemicarbazones have been studied as corrosion inh... more Selected substituted thiosemicarbazides and thiosemicarbazones have been studied as corrosion inhibitors for mild steel in sulphuric acid using electrochemical techniques. The impedance measurements typically gave a single relaxation or semicircle comprising the charge transfer resistance in parallel with the double-layer capacitance. Inhibitor efficiencies and the adsorption isotherms were calculated from the charge transfer resistance values, whilst the capacitance-potential diagrams provided mechanistic information on the adsorption of these types of compounds. Thiosemicarbazide and its derivatives act as mixed adsorption type inhibitors, increased adsorption resulting from an increase in the electron density at the reactive) C=S group by suitable substitution of a terminal hydrogen in the hydrazino or thiamido groups of the thiosemicarbazide molecule. The substituted compounds were classified into three distinct groups according to their molecular structure and electrochemical response.