Aluminium In HCl Research Articles

Electrochemical evaluation of an Acanthocereus tetragonus aqueous extract on aluminum in NaCl (0.6 M) and HCl (1 M) and its modelling using forward and inverse artificial neural networks

• Acanthocereus tetragonus aqueous extract was evaluated in acidic and neutral media as a corrosion inhibitor. • Forward ANNs were trained with two Aluminum electrochemical evaluations databases. • Larger databases were calculated from Forward ANNs. • Inverse ANNs (IANNs) were trained with the large databases. • Time and concentration of the Acanthocereus tetragonus extract were found from optimal IANNs. An innovative numerical method based on a machine learning approach is presented in order to model the electrochemical behaviour of an Acanthocereus tetragonus aqueous extract on Aluminum in acidic and neutral media. Experimental data of an electrochemical evaluation of Aluminum in HCl (1 M) and NaCl (0.6 M) were used to generate the training set for forward Artificial Neural Networks (ANN). Later, this nonlinear relationship is inverted and refined with the purpose of design and train an inverse ANN that solves the following inverse problem: to find the concentration of a green corrosion inhibitor and the exposure time as a function of pH values, real and imaginary impedance values, and a frequency range of measure between 10,000 and 0.01 Hz.

Slippery and Sticky Superoleophobicities on Hierarchical Aluminum Surfaces Fabricated by Electrochemical Etching and Anodizing Methods

Slippery and sticky superoleophobic aluminum surfaces were fabricated by electrochemical etching and anodizing methods. Collective structures of sub-micrometer-scale cubic-shaped aluminum were formed by electrochemical etching of high-purity aluminum in HCl. The etched specimens were then anodized in H4P2O7 to form anodic alumina nanofibers (AANFs) on the cubic aluminum surface, resulting in a hierarchical aluminum-alumina structure. As the water/oil-repellent self-assembled monolayers were formed on their surfaces, the superoleophobicity of dodecane was more than 150° in the advancing contact angle exhibited on the anodizing surfaces. Conversely, the receding contact angle changed drastically with anodizing time because of the different nanomorphology of AANFs; short anodizing caused slippery superoleophobicity with high contact angle values, whereas long anodizing resulted in sticky superoleophobicity with 0°. We demonstrated the slipping behavior of dodecane droplets on superoleophobic aluminum surfaces with completely opposite sliding properties. The corrosion resistant property of the superoleophobic aluminum surface was also investigated by the measurements of potentiodynamic curve in a 3.5 wt% sodium chloride solution.

CHEMICAL CHARACTERIZATION OF VOLATILE EXTRACT OF ARTEMISIA HERBA-ALBA AND STUDY OF ITS ANTIOXIDANT, ANTIMICROBIAL AND ANTIFUNGAL ACTIVITIES AND ITS INHIBITIONORY EFFECT ON CORROSION OF ALUMINUM IN HYDROGEN CHLORIDE SOLUTION

The chemical composition of the essential oil of Artemisia herba-alba obtained by hydrodistillation was determined by chromatographic analysis (GC and GC-MS). Seventy-nine components were identified, which accounted for 93.3% of the total essential oil. The major components were chrysanthenone (24.1 %), camphor (16,2%), α-thujone (12.8 %) and 1,8-cineole (9.3%). The investigated volatile extract showed potency antimicrobial activity, against all the studied bacterial strains (MIC values not exceeding 2 μg/mL). Also, this oil showed substantial antifungal activity MIC less than 0.5μg/mL for Fusarium oxysporum and Penicillium expansum. Compared to BHA and BHT which were acted as positive controls, the essential oil was the less active to inhibit the free radical DPPH insofar it failed to reach a scavenging capability of 50%. The oil was also tested for its corrosion inhibitor of pure aluminum in HCl (1 mol./L) using electrochemical techniques (potentiodynamic polarization, open circuit potential, and electrochemical impedance spectroscopy) and gravimetric measurements. The results reveal that the inhibition effectiveness was dose-dependent of the oil concentration (maximum corrosion inhibition = 94.3% for an optimal concentration of 0.8 g / L). These findings suggest that this essential oil may be a new green inhibitor agent against corrosion in hydrogen chloride solution media and could be used on food systems as an effective inhibitor of foodborne pathogens as well as for pharmaceutical applications.

Ball-type phthalocyanines and reduced graphene oxide nanoparticles as separate and combined corrosion inhibitors of aluminium in HCl

Corrosion inhibition performances and adsorption behaviour at the aluminum-HCl solution interface were investigated for reduced graphene oxide nanosheets (rGONS), tetrakis-[4,4′-((4-(benzo[d]thiazol-2-yl)-1,2-bis(phenoxy)] (diphthalocyaninato gallium (III) chloride) (2) and tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyaninato gallium(III) chloride) (1). Corrosion inhibition effects of rGONS, 1 and 2 were evaluated alone and in combination in 1.0 M hydrochloric acid solution using electrochemical techniques. The mechanism of aluminum corrosion inhibition revealed predominantly anodic character for rGONS and predominantly cathodic character for 1, 2, and conjugates with rGONS . The polarization technique gave inhibition efficiency values of 96.5% and 96.9% respectively for 1 and 2, which increased in the presence of rGONS to 97.4% and 98.1%, respectively, for the highest concentrations of 1 and 2. Scanning electron microscopy revealed effective metal surface protection by the inhibitors by formation of protective films.

Corrosion Inhibition of Aluminum by Cerumium rubrum Extract in Hydrochloric Acid Environment

The inhibitive action of Cerumium rubrum extract against the corrosion of Al in a 1-M HCl environment was examined using conventional electrochemical and chemical methods. The results indicate that the extract exhibited excellent anticorrosive properties of aluminum in HCl reaching approximately 86.2% at 300 ppm at 318 K. It obeys the Langmuir adsorption isotherm. Polarization curves indicate that the extract acts as a mixed-type inhibitor. Moreover, the kinetic and thermodynamic parameters for the corrosion reaction were estimated and debated. The covering film established by the extract was checked by several techniques. All techniques gave similar results.

Evaluation of corrosion behaviour of aluminum in different environment

The corrosion behaviour of aluminum in hydrochloric, nitric, sulfuric and phosphoric acids was investigated using weight loss method. The results shows that the corrosion rate of aluminium in HCl, H 3 PO 4 , H H 3 PO 4 > H HNO 3 Keywords : aluminum, weight loss, corrosion rate, thermodynamic and kinetic parameters

ChemInform Abstract: Polymeric Complexes ‐ LXII. Coordination Chemistry of Supramolecular Schiff Base Polymer Complexes ‐ A Review

AbstractReview: 30 refs.

Corrosion of iron and aluminum in acidic and basic media: theoretical and experimental investigation

Purpose The purpose of this investigation is to study the corrosion behavior of iron and aluminum in HCl and NaOH media by means of theoretical and experimental approaches. Design/methodology/approach For theoretical investigations, the quantum chemical calculation was performed. In this regard, the adsorption of OH− and Cl− on iron and aluminum surfaces was investigated. Furthermore, the natural bond orbital for the direction and magnitude of charge transfer interactions were calculated. In addition, the electrochemical evaluations based on potentiodynamic experiments were carried out. Findings The quantum chemical calculation results showed that the charge transfer from OH− to the iron surface is more than that from Cl−, and also the charge transfer from Cl− is more than that from OH− to aluminum cluster. Furthermore, these anions donate more electrons to the iron cluster than to the aluminum cluster. The experimental data showed that the rate of corrosion of iron in 1.0M NaOH solution was less than in 1.0M HCl solution. The corrosion of aluminum in HCl solution was less than that in NaOH solution. The rate of corrosion of iron in both solutions was less than that of aluminum. Originality/value The findings of this paper indicate that calculations based on the natural bond orbital analysis of the charge transfer rates from OH− and Cl− to the iron or aluminum surfaces, and their comparison with experimental results, exhibited excellent agreement.

Thermodynamics and Kinetics of Inhibition of Aluminum in Hydrochloric Acid by Date Palm Leaf Extract

The corrosion behavior of commercial aluminum in HCl was investigated by gravimetric method in absence and presence of date palm leaf extract (DPLE) as inhibitor. Corrosion rates in absence of extract ranged from 2.4-8.0 mg/cm 2 /h in the temperature range 20- 50oC but decreased down to 0.30-2.6 mg/cm 2 /h in presence of the inhibitor. Hot-water extract of date palm leaves has shown inhibition efficiency (IE) of 40- 88%at the tested conditions. IE was found to increase with increasing inhibitor concentration from 0.2 to 0.6 g/L and decrease as temperature increased. Data showed that Langmuir adsorption isotherm represents surface coverage versus extract concentration data indicating that inhibition is due to monolayer adsorption of extract components on aluminum surface. Low activation energy and enthalpy values support physical adsorption mechanism. SEM-EDS microanalysis of aluminum surface supported the inhibitive effect of the extract at the metal surface.© JASEM

Cashew Nut Testa Tannin: Assessing its Effects on the Corrosion of Aluminium in HCl

Cashew nut testa tannin [CASTAN] has been found to inhibit the corrosion of aluminium in hydrochloric acid solutions using gravimetric, thermometric and UV/visible spectrophotometric techniques. CASTAN inhibition was by adsorption on aluminium following Temkin isotherm in 0.1 M HCl and Langmuir isotherm in 0.5 M and 2.0 M HCl at 303 Kelvin. Physical adsorption on aluminium has been proposed in studied HCl solutions; therefore, CASTAN is a cathodic inhibitor. Earlier reports [1] showed CASTAN to contain quercetin, azaleatin, catechin, epicatechin, cyanidin and delphinidin. However, UV/visible spectrophotometric analysis of CASTAN in ethanol reveals quercetin as its major component. This work therefore investigated the correlation between computed molecular parameters and inhibitive properties of CASTAN and adsorption sites on its components. Calculated quantum chemical parameters namely: E HOMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), energy gap ( �E) and dipole moment ( μ ) suggest that CASTAN is a soft inhibitor and it’s components inhibited aluminium corrosion in protonated forms. Calculated Mulliken charges implicated some electron rich sites, namely: the aromatic and conjugated C=C, C=O and O-H as adsorption sites on the inhibitor molecules. Proposed kinetic model reveals complex reaction mechanism, parallel reactions, for aluminium corrosion inhibition by CASTAN.

Corrosion Inhibition of Aluminium in HCl by Amine Modified Epoxy Resin

N-Butyl amine has been grafted unto Dow epoxy resin. The product was evaluated as an acid inhibitor by gravimetric techniques. The reduction in corrosion of aluminium in 1 M HCl solution was 92% at and 83% at with an inhibitor concentration of 100 ppm. The corrosion rate at this concentration was and mm/yr at and . For the specimens in HCl without inhibitor at 10-hour immersion period, the corrosion rate was and mm/yr, respectively, at and . Data obtained correlate with Langmuir isotherm.

Corrosion Prevention of Aluminium in 1 M HCl by Surface Deposition of Nickel Titanate

A different approach for protecting the aluminium in 1M HCl is done by strengthening the surface oxide film of aluminium with nickel titanate particles. Weight loss methods, open circuit potential measurements and polarization techniques are used to measure the corrosion behaviour of aluminium samples. The corrosion rate of nickel titanate deposited aluminium shows lower values compared to pure aluminium in HCl medium. The intermixing of aluminium oxide with nickel titanate enhances the corrosion resistance property of the aluminium oxide layer on the surface of aluminium and thereby reduces the coulombic and non-coulombic loss of metal.

Inhibition effect of Dendrocalamus brandisii leaves extract on aluminum in HCl, H3PO4 solutions

The inhibition effect of Dendrocalamus brandisii leaves extract (DBLE) on the corrosion of aluminum in HCl, H3PO4 solutions was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) methods. Effects of temperature, immersion time and acid concentration on corrosion inhibition were fully discussed. The results show that DBLE is a good inhibitor in 1.0M HCl, while a moderate inhibitor in H3PO4. The adsorption of DBLE on aluminum surface obeys Langmuir isotherm in both acids. DBLE acts as a cathodic inhibitor in HCl, while a mixed-type inhibitor in H3PO4.

Corrosion Inhibition of Aluminium by Treculia Africana Leaves Extract in Acid Medium

The inhibitive effect of Treculia Africana leaves extract (TALE) in the corrosion of aluminium in HCl solution was studied using weight loss and thermometric methods at 30 - 60 oC. The results showed that TALE acted as a corrosion inhibitor of aluminium in HCl. Inhibition efficiency increased with increase in TALE concentration, but decreased with increase in temperature. TALE interaction with the metal surface was found to obey Freundlich and El-Awady adsorption isotherms. The obtained heats of adsorption values were negative. A phenomenon of physical adsorption is proposed for the adsorption behavior of TALE.

Experimental and theoretical study of the inhibition effects of some Schiff bases as corrosion inhibitors of aluminium in HCl

AbstractThe inhibition efficiencies of two new synthesized Schiff bases have been investigated for aluminium in 0.5 M HCl solution using experimental and theoretical methods. Potentiodynamic polarization and EIS method were used to determine the inhibition efficiencies. From the experimental results it has been found that both compounds adsorb on the aluminium surface according to the Temkin adsorption isotherm. Quantum chemical calculations were further applied to reveal the adsorption structure and explain the experimental results. A good correlation between the quantum chemical parameters and the experimental inhibition efficiency has been found.

Fundamental studies of aluminum corrosion in acidic and basic environments: Theoretical predictions and experimental observations

Using quantum electrochemical approaches based on density functional theory and cluster/polarized continuum model, we investigated the corrosion behavior of aluminum in HCl and NaOH media containing phenol inhibitor. In this regard, we determined the geometry and electronic structure of the species at metal/solution interface. The investigations revealed that the interaction energies of hydroxide corrosive agents with aluminum surface should be more negative than those of chloride ones. The inhibitor adsorption in acid is more likely to have a physical nature while it appears as though to be chemical in basic media. To verify these predictions, using Tafel plots, we studied the phenomena from experimental viewpoint. The studies confirmed that the rate of corrosion in alkaline solution is substantially greater than in HCl media. Moreover, phenol is a potential-molecule having mixed-type inhibition mechanism. The relationship between inhibitory action and molecular parameters was discussed and the activity in alkaline media was also theoretically anticipated. This prediction was in accord with experiment.

Electrograining of aluminium in HCl: effect of the alloy for high‐speed processing lines

AbstractElectrograining of aluminium in hydrochloric acid is one of the most commonly used processes for manufacturing printing lithographic plates. Two of the main features to be taken into account are the final morphology of the electrograined surface and the susceptibility of the alloy to be processed or, more specifically, the speed of the processing line. Both issues determine the efficiency of the production in terms of quality and time. In this work, a widely used commercial aluminium alloy (1050) is compared with a new experimental one (1050 modified with Zn) and with a higher strength alloy (namely 1020). In order to analyse their response to a.c. graining in HCl for high‐speed lines, some techniques such as image analysis or interferometry have been used. In general, the alloys doped with Zn and Mg present a better response to litho processing in terms of graining activity and reduction of streakiness when treatment of lower time periods is applied due to their influence as pitting initiators. Copyright © 2010 John Wiley & Sons, Ltd.

Synergistic Inhibition Between Polyvinylpyrollidone and Iodide Ions on Corrosion of Aluminium in HCl~!2008-10-03~!2008-11-08~!2009-01-06~!

Synergistic Inhibition Between Polyvinylpyrollidone and Iodide Ions on Corrosion of Aluminium in HCl~!2008-10-03~!2008-11-08~!2009-01-06~!

Effect of Anions on the Corrosion Inhibition of Aluminum in HCl using Ethyl Trimethyl Ammonium Bromide as Cationic Inhibitor

Effect of Anions on the Corrosion Inhibition of Aluminum in HCl using Ethyl Trimethyl Ammonium Bromide as Cationic Inhibitor

Eco-friendly Inhibitors from Naturally Occurring Exudate Gums for Aluminium Corrosion Inhibition in Acidic Medium

Exudates gums from Pachylobus edulis (PE) and Raphia hookeri (RH) were evaluated as corrosion inhibitors for aluminium in HCl using weight loss and thermometric measurements at 30 – 60 o C. The exudates were found to retard corrosion rate of aluminium. The inhibition efficiency (%1) increased with increase in concentration of the exudates. Increase in temperature increased the corrosion rate in the absence and presence of inhibitors but decreased the inhibition efficiency. Both PE and RH exudate gums were 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. Exudate gum from RH was found to be a better inhibitor than PE.