Corrosion Inhibition Of Aluminum Research Articles

Corrosion inhibition of aluminum in 1 M H3PO4 solutions by ethanolamines

The inhibitive effect of the investigated compounds (ethanolamine (I), diethanolamine (II) and triethanolamine (III)) on the corrosion behavior of aluminum in 1M H3PO4 solution using weight loss, galvanostatic polarization and quantum chemical calculation methods was studied. The inhibition efficiency was found to depend on type and concentration of the additives and also on temperature. The effect of addition of halide ions to various concentrations of these compounds has also been studied. The apparent activation energy (Ea) and other thermodynamic parameters for the corrosion process have also been calculated and discussed. The galvanostatic polarization data indicated that these inhibitors were of mixed-type. The slopes of the cathodic and anodic Tafel lines (βc and βa) are approximately constant and independent of the inhibitor concentration. The adsorption of these compounds on aluminum surface has been found to obey the Freundlich adsorption isotherm. Some quantum chemical parameters and Mulliken charge densities for investigated compounds were calculated by the AM1 semi-empirical method to provide further insight into the mechanism of inhibition of the corrosion process. The theoretical results are then compared with experimental data.

Novel package for inhibition of aluminium corrosion in alkaline solutions

Inhibition of aluminium corrosion in 2 M sodium hydroxide solution by a package composed of the cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and lupine seed extract has been investigated employing different electrochemical techniques and chemical gasometry measurements. Potentiodynamic polarization curve measurements showed that lupine seed extract controls both the anodic dissolution of aluminium and the hydrogen gas evolved at the cathodic sites of aluminium surface. Nyquist plots showed two capacitive semicircles in the high and low frequency regions separated by an inductive loop at intermediate frequencies. The inductive loop may be explained by the occurrence of adsorbed intermediates on the surface. A proposed equivalent circuit was used to analyse the impedance spectra for aluminium in NaOH solutions. The corrosion inhibition data have been analysed using different isotherms. The results showed excellent agreement between the kinetic–thermodynamic model and Flory–Huggins isotherm. Gasometry measurements showed that the Inhibitive effect of the surfactant increases at a composition around its critical micelle concentration (cmc). The presence of both the surfactant and lupine seed extract did not indicate synergistic action between them. The mode of adsorption of the surfactant molecules corresponding to their structure is also discussed.

Cu(II), Co(II) and Ni(II) complexes of –Br and –OCH2CH3 substituted Schiff bases as corrosion inhibitors for aluminium in acidic media

A group of Cu(II), Ni(II) and Co(II) complexes of –Br and –OCH2CH3 substituted Schiff bases as a new class of corrosion inhibitors for aluminium has been studied in 0.1 M HCl by the addition of 10 ppm compound using potentiodynamic polarization, electrochemical impedance spectroscopy, linear polarization methods and gas evolution tests at 25 °C. The inhibition efficiencies obtained from all methods employed are in good agreement. Results show Ni(II) complex of –OCH2CH3 substituted Schiff bases was the best inhibitor with a mean efficiency of 69% at 10 ppm additive concentration. The potentiodynamic polarization curves showed both the cathodic and the anodic processes of aluminium corrosion were suppressed, and the Nyquist plots of impedance gave mainly a capacitive loop. Scanning electron microscopy (SEM) was done from the surface of the exposed sample indicating uniform film on the surface.

An interesting and efficient green corrosion inhibitor for aluminium from extracts of Chlomolaena odorata L. in acidic solution

The leaf extracts of Chromolaena odorata L. (LECO) has been studied as a possible source of green inhibitor for corrosion of aluminium in 2 M HCl using gasometric and thermometric techniques at 30 and 60 °C. Results obtained showed that the LECO functioned as an excellent corrosion inhibitor for aluminium in the acidic environment. Inhibition efficiency increased with extract concentration but decreased with temperature. The adsorption of LECO on Al surface is in accord with Langmuir adsorption isotherm. Both kinetic and thermodynamic parameters governing the adsorption process were calculated and discussed. From the experimental results obtained, it can be concluded that LECO which are biodegradable, environmentally benign, and are obtained from a renewable resource with minimal health and safety concerns have the potential to be a cost effective alternative to synthetic corrosion inhibitors. This present study provides new information on the inhibiting characteristics of LECO extract under specified conditions. The environmentally friendly inhibitor could find possible applications in metal surface anodizing and surface coating in industries.

Corrosion Inhibition of Aluminium in Acid Media By Citrullus Colocynthis Extract

Inhibition of corrosion of aluminium in acid solution by methanol extract of Citrullus colocynthis plant has been studied using mass loss and thermometric measurements. It has been found that the plant extract act as a good corrosion inhibitor for aluminium in all concentrations of sulphuric and hydrochloric acid solution. The inhibition action depends on the concentration of acid and inhibitor. Results for mass loss and thermometric measurement indicate that inhibition efficiency increase with increasing inhibitor concentration. The inhibition action of the plant extract is discussed in view of Langmuir adsorption isotherm. It has been observed that the adsorption of the extract on aluminium surface is a spontaneous process. The plant extract provides a good protection to aluminium against corrosion.

Leaves extract of Ananas sativum as green corrosion inhibitor for aluminium in hydrochloric acid solutions

The inhibition of corrosion of aluminum in hydrochloric acid solutions by the ethanolic extract of the leaves of Ananas sativum was studied using weight loss and hydrogen evolution methods. It was found that the plant extract retarded the acid induced corrosion of aluminum. Inhibition efficiency increased with increasing concentration of the extract and temperature. Adsorption studies revealed that Langmuir adsorption isotherm is the best adsorption model applicable to the adsorption of A. sativum on aluminum surface. Activation parameters such as activation energies (E a), activation enthalpy (ΔH o), and activation entropy (ΔS o) were evaluated from the effect of temperature on the corrosion and inhibition processes.

Electrochemical investigation and modeling of corrosion inhibition of aluminum in molar nitric acid using some sulphur-containing amines

Chemical and electrochemical measurements incorporated with quantum chemical calculations and molecular dynamics simulations were used to study the corrosion inhibition characteristics of some thiosemicarbazone derivatives on the inhibition of aluminum corrosion in 1.0 M HNO 3. Polarization curves demonstrated that the thiosemicarbazone derivatives were of mixed-type inhibitors. EIS plots indicated that the addition of thiosemicarbazone derivatives increases the charge-transfer resistance of the corrosion process, and hence the inhibition performance. The molecular dynamics simulation results show that the three thiosemicarbazone derivatives can adsorb on the A 2O 3 (1 1 1) surface through the sulphur and nitrogen atoms as well as π-electrons in the pyridyl structure.

Corrosion Inhibition of Aluminum by Organic Coatings Formulated with Hydrotalcite-Vanadate Pigments

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Study on the effect of vanillin on the corrosion inhibition of aluminum alloy

The effect of vanillin on the corrosion inhibition of aluminum (Al) alloy in seawater was studied by potentiodynamic polarization (PP), linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) techniques. The surface morphology after its exposure to seawater with and without vanillin was examined by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). All the studied parameters showed good inhibitive characteristics against the corrosion of Al alloy in the tested solution, and their performance was observed to increase with the inhibitor concentration. Polarization data indicated that the studied inhibitor is a mixed-type inhibitor. Linear polarization and EIS studies showed that there were significant increases in the overall resistance after the addition of vanillin. The adsorption of inhibitor on Al alloy was found to obey the Langmuir adsorption isotherm. The analysis of SEM and EDS confirmed the formation of precipitates of vanillin on the metal surface, which reduced the overall corrosion reaction.

Acid‐dyes as corrosion inhibitors for mechanically pretreated aluminum

PurposeThe purpose of this paper is to provide acid‐dyes, known for the dyeing of porous aluminum oxide films, as inhibitors of the corrosion of aluminum in neutral chloride solutions.Design/methodology/approachPotentiodynamic polarization plots are recorded on mechanically pretreated aluminum using a three‐electrode cell containing 0.01 M NaCl solution with or without 0.025 mM of the acid‐dyes monosulfonic methyl orange (MO), disulfonic chromotrop RR (CH), disulfonic alphazurine A (AZ) and trisulfonic light green SF yellowish (LG). The X‐ray fluorescence technique is used in certain cases for the estimation of sulfur net content of the surface of the probes and thus of the concentration of the adsorbed dye.FindingsThe inhibition efficiency of acid dyes on corrosion of mechanically pretreated aluminum seems to be related more to the presence of a following quinonoid structure which probably contributes more to the formation of mono‐ or bi‐dentate compounds with the aluminum cations in the substrate than to the number of sulfonic groups in their molecule. Thus, the triphenylmethane dyes LG and, to a greater extent AZ, having this quinonoid structure means they are more efficient as corrosion inhibitors in near‐neutral chloride solution than the azo dyes MO and CH, that do not have it.Practical implicationsSelected acid‐dyes such as triphenylmethane sulfonic‐dyes, which have found wide application in the dyeing industry, seem to protect aluminum against the corrosive action of chlorides.Originality/valueThis paper is intended to be the nucleus for the electrochemical studies of the effectiveness of acid dyes as corrosion inhibitors for aluminum.

Relation between kinetic regularities of the inhibition of aluminum corrosion with metal salts and the formation of contact deposits on the aluminum surface in chloride electrolytes

Under contact-exchange conditions at high metal depolarization, the regularities of the inhibition of aluminum corrosion in hydrochloric electrolytes containing tin and cadmium chlorides or their equimolar mixture are studied. For the inhibiting composition, the mutual effect of the components is estimated taking into account the actual component contents in the contact deposit, which was determined with the use of atomic absorption spectroscopy.

Corrosion inhibition of aluminum in 2.0 M hydrochloric acid solution by the acetone extract of red onion skin

The inhibition efficiency of acetone extract of red onion skin on aluminium in hydrochloric acid solutions has been evaluated by weight loss techniques. Values of inhibition efficiency obtained are dependent upon the concentration of inhibitor and temperature. Generally, inhibition was found to increase with inhibitor concentration, half-life, activation energy but decrease with temperature and first-order rate constant at the temperatures studied. Physical adsorption mechanism has been proposed for the inhibition and Langmuir adsorption isotherm was obeyed. The compound responsible for the inhibitory action of red onion skin is Quercetin. Red onion skin is an inhibitor of aluminium corrosion in 2 M hydrochloric acid solution. Key words: Corrosion inhibition, aluminium, weight loss, red onion skin, hydrochloric acid.

Inhibition of Aluminium Corrosion in Hydrochloric Acid Using Nizoral and the Effect of Iodide Ion Addition

The effect of nizoral (NZR) on the corrosion inhibition of aluminium alloy AA 1060 in 2 M HCl solution was investigated using the mylius thermometric technique. Results of the study revealed that nizoral acts as corrosion inhibitor for aluminium in the acidic medium. In general, at constant acid concentration, the inhibition efficiency increases with increase in the inhibitor concentration. The addition of KI to the inhibitor enhanced the inhibition efficiency to a considerable extent. The adsorption of nizoral onto the aluminium surface was found to obey the Fruendlich adsorption isotherm. The value of the free energy for the adsorption process shows that the process is spontaneous.

The Inhibition of aluminium corrosion in hydrochloric acid solution by exudate gum from Raphia hookeri

The corrosion inhibition of aluminium in HCl solution in the presence of exudate gum from Raphia hookeri at temperature range of 30–60°C was studied using weight loss and thermometric techniques. The exudate gum acts as an inhibitor in the acid environment. The inhibition efficiency increases with increase in inhibitor concentration but decreases with an increase in temperature. The inhibitive effect of the Raphia hookeri exudate could be attributed to the presence of some phytochemical constituents in the exudate which is adsorbed on the surface of the aluminium metal. The exudate gum was found to obey Temkin adsorption isotherm and Kinetic–Thermodynamic Model of El-Awady et al. at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameters obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous.

Ketonic secondary Mannich bases as corrosion inhibitors for aluminium

The inhibition action of some ketonic secondary Mannich base derivatives on the corrosion of aluminium in 2M HCl solution was investigated using weight loss and galvanostatic polarization techniques. The inhibition efficiencies calculated from the two different methods are in good agreement. The corrosion rate of Al was found to be a function of concentration of inhibitor, temperature of the medium and the nature of the inhibitor. The effect of temperature on the corrosion rate was studied in order to obtain the kinetic and thermodynamic parameters of aluminium corrosion. The inhibitive action of these compounds was discussed in terms of blocking the electrode surface by the adsorption of the molecules through the active centers contained in their structure. The adsorption process follows Temkin adsorption isotherm.

Corrosion inhibition of aluminum 6063 using some pharmaceutical compounds

The corrosion inhibition characteristics of some pharmaceutical compounds on aluminium 6063 in 0.5 mol l−1 H3PO4 has been studied using weight loss and galvanostatic polarization techniques. Results showed that the inhibition occurs through adsorption of the inhibitor molecules on the metal surface. The inhibition efficiency increased with increasing inhibitor concentration, but decreased with increasing temperature. The adsorption of first group pharmaceutical compounds on the metal surface is found to obey Frumkin’s adsorption isotherm, but the adsorption of second group pharmaceutical compounds is found to obey Temkin’s adsorption isotherm. Thermodynamic parameters for adsorption process were determined. Galvanostatic polarization studies showed that first and second groups’ pharmaceutical compounds are mixed-type inhibitors and the results obtained from the two techniques are in good agreement.

Corrosion inhibition of aluminum in hydrochloric acid solution by alkylimidazolium ionic liquids

The effects of newly synthesized three alkylimidazolium ionic liquids—1-butyl-3-methylimidazolium chlorides (BMIC), 1-hexyl-3-methylimidazolium chlorides (HMIC) and 1-octyl-3-methylimidazolium chlorides (OMIC)—on the corrosion of aluminum in 1.0 M HCl were investigated using potentiodynamic polarization, electrochemical impedance spectroscopy and weight loss methods. All measurements showed that the inhibition efficiency increased with increase in the concentration of inhibitor and the effectiveness of these inhibitors was in the order of OMIC > HMIC > BMIC. Polarization curves revealed that the studied inhibitors were mixed type inhibitors. The adsorption of the inhibitors on the aluminum surface obeyed Langmuir adsorption isotherm and had a physical mechanism. The effect of temperature on the corrosion behavior in the presence of 5 × 10 −3 M of inhibitors was studied in the temperature range of 303–333 K. The associated activation energy of corrosion and other thermodynamic parameters such as enthalpy of activation (Δ H), entropy of activation (Δ S), adsorption equilibrium constant ( K ads ) and free energy of adsorption (Δ G ads ) were calculated to elaborate the mechanism of corrosion inhibition.

Corrosion Inhibition of Aluminum in Hydrochloric Acid Solution Using Potassium Iodate Inhibitor

The inhibition effect of potassium iodate on the corrosion of aluminum in 2M HCl has been studied by weight loss, polarization and electrochemical impedance spectroscopy (EIS) measurements. It has been found that KIO3 acts as an excellent inhibitor. Inhibition efficiency with 100 ppm inhibitor was very high. Polarization curves reveal that the used inhibitor is a mixed type inhibitor. The surface adsorption of KIO3 leads to a decrease of double layer capacitance as well as an increase of polarization resistance. The adsorption of the inhibitor on the aluminum surface is in agreement with Temkin adsorption isotherm.

Electrochemical and molecular dynamics simulation studies on the corrosion inhibition of aluminum in molar hydrochloric acid using some imidazole derivatives

The corrosion inhibition and adsorption characteristics of three selected imidazole derivatives namely, 2-amino-4,5-imidazoledicarbonitril (AID), 5-amino-4-imidazolecarboxamide (AIC) and imidazole (IM) on aluminum in 1.0 M HCl was investigated at 25 °C. Measurements were carried out under various experimental conditions using chemical (weight loss), and electrochemical (Tafel polarization and impedance) methods. Molecular dynamics (MD) method and density functional theory were also applied here for theoretical study. Results obtained showed that inhibition efficiency of these compounds increases with increase in their concentrations due to the formation of a surface film on the aluminum surface. Adsorption energy as well as hydrogen bond length calculations showed that AID was the best corrosion inhibitor among the tested imidazole derivatives. Polarization measurements reveal that the selected imidazole derivatives function mainly as cathodic-type inhibitors. Physisorption, followed by chemisorption was proposed as the mechanism for the inhibition process. Adsorption via H-bond formation was also considered here. Results obtained from theoretical study were found to confirm experimental findings.

Antifungal drugs as corrosion inhibitors for aluminium in 0.1 M HCl

The inhibitive capabilities of Clotrimazole (CTM) and Fluconazole (FLC), two antifungal drugs, on the electrochemical corrosion of aluminium in 0.1 M HCl solution has been studied using weight loss measurements at 30 and 50 °C. The results indicate that both compound act as inhibitors in the acidic corrodent. At constant acid concentration, the inhibition efficiency (% I) increased with increase in the concentration of the inhibitors. Increase in temperature increased the corrosion rate in the absence and presence of the inhibitors but decreased the inhibition efficiency. CTM and FLC adsorbed on the surface of aluminium according to the Langmuir adsorption isotherm model at all the concentrations and temperatures studied. Phenomenon of physical adsorption is proposed from the activation parameter obtained. Thermodynamic parameters reveal that the adsorption process is spontaneous. The reactivity of these compounds was analyzed through theoretical calculations based on AM1 semi-empirical method to explain the different efficiencies of these compounds as corrosion inhibitors. CTM was found to be a better inhibitor than FLC.