Aluminium In Alkaline Medium Research Articles

Corrosion Inhibition Potentials of A. mossambicensis and E. sonchifolia Leaves' Extracts on Aluminium in Alkaline Media: Insights from Gravimetric and Electrochemical Studies

Corrosion Inhibition Potentials of A. mossambicensis and E. sonchifolia Leaves' Extracts on Aluminium in Alkaline Media: Insights from Gravimetric and Electrochemical Studies

Studies on the corrosion inhibition properties of mimosa pudica on aluminium in alkaline medium

In the present work, the effect of Mimosa pudica leaves extract on the corrosion of aluminium in 1N NaOH was studied using weight loss measurements and electrochemical techniques such as Tafel Polarization and Electrochemical Impedance Spectroscopy. A maximum inhibition efficiency of 78% is observed at 1.2g/L of inhibitor concentration which was found to be consistent across all the methods employed. The temperature dependency inhibitive properties of the selected inhibitor were studied in the range 303- 333K. The adsorption behavior of the inhibitor on the surface of aluminium was studied by fitting Langmuir adsorption isotherm and the nature of adsorption was found to be physisorption. Metallurgical microscopic analysis of the aluminium surface with and without the inhibitor further validated the results.

Hydrogen Production on Aluminum in Alkaline Media

Hydrogen Production on Aluminum in Alkaline Media

Derris Indica Leaves Extract as a Green Inhibitor for the Corrosion of Aluminium in Alkaline Medium

Derris Indica Leaves Extract as a Green Inhibitor for the Corrosion of Aluminium in Alkaline Medium

Synthesis and corrosion inhibition studies of modified polyacrylic acid bearing triazole moieties on aluminium in alkaline medium

Novel modified Polyacrylic acid (ACTP) bearing triazole pendant moieties prepared with polyacrylyl chloride and 3-amino-1,2,4-triazole-5-thiol through polycondensation reaction. The synthesized polymer was characterized using nuclear magnetic resonance (lH-NMR, 13C-NMR), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive studies (EDAX) and thermogravimetric (TGA) studies. The ACTP polymer was tested as corrosion inhibitor with aluminium metal in alkaline medium and their results were compared with synthesized simple polyacrylic acid (PAA). Gravimetric, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques were used to test the efficiency of the corrosion inhibitor. Activation energy and free energy for inhibition reaction supports both chemical and physical adsorption mechanism, with better inhibition efficiency. Potentiodynamic polarization curves validated that the corrosion inhibitors behave an anodic type.

Corrosion Mitigation of Gray Cast Iron and Aluminum in NaOH Using Water Hyacinth (Eichhornia crassipes) Plant Extract

This research focused on the corrosion behavior of gray cast iron and aluminum in alkaline medium (0.5 M NaOH) with and without inhibitor (water hyacinth Eichhornia crassipes extract) of varying concentrations of 5%, 10%, 15%, 20% and 25%. The corrosion rates of the metal samples were investigated using the weight loss and electrochemical methods alongside the formulation of a dispersant using readily available chemicals to develop a colloidal solution of the extract produced by hot water digestion of the water hyacinth plant leaves. The metallography tests of control samples as well as the most and least corroded samples were carried out using Optical Microscope (OM). The results revealed that the aluminum resulted in minimum corrosion rate of 0.000483 mg/mm2/yr with inhibitor efficiency of 98.93% obtained for sample A5 (25% extract from water hyacinth) while for the gray cast iron, a minimum corrosion rate of -4.4E-05 mg/mm2/yr with inhibitor efficiency of 566.6% obtained for sample C3 (15% extract from water hyacinth). The electrochemical result of aluminum showed increase in corrosion potential from -1.494 VAg/AgCl to -1.482 V Ag/AgCl and that of gray cast iron from -0.5436 VAg/AgCl to -0.2839 VAg/AgCl upon increase in inhibitor concentration. Therefore, the use of water hyacinth (Eichhornia crassipes)extract reduced the corrosion or dissolution rate of gray cast iron and aluminum in (NaOH) sodium hydroxide medium.

Effect of amino acid on the passivation, corrosion and inhibition behavior of aluminum alloy in alkaline medium

The effect of L-methionine (L-Met) on the passivation and corrosion inhibition of aluminum alloy was investigated in carbonate medium in presence of chloride ions. This inhibitive action against the corrosion of aluminum in corrosive solution was investigated at 298 K using potentiodynamic polarization curves (PDP), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results obtained from the polarization curves reveal that the aluminum in alkaline medium exhibits a phenomenon of passivation with breakdown of passivity. Temperature effect on the corrosion behavior with the addition of (L-Met) studied in the range of temperature from 298 to 328 K. The inhibition efficiency decreases slightly with the increase in the temperature. Results show that L-Met is a good inhibitor and inhibition efficiency reach 87,23% at 10 −3 M. The electrochemical results are confirmed by scanning electron microscopy (SEM). The adsorption of this compound on aluminum surface obeys Langmuir’s adsorption isotherm. The kinetic and thermodynamic parameters were determined and discussed.

Thermodynamic analysis for the separation of tungsten and aluminium in alkaline medium using solvent extraction

The thermodynamic equilibrium diagrams for distribution of species at different pH values of tungsten and aluminium with the systems of W-H2O and Al-H2O at 298K were established, separately. The effects of the concentrations of W, Al and Na2CO3 in feed, and the equilibrium pH on the extractions of W and Al were investigated. Thermodynamic analysis results revealed that the tungsten and aluminium exist as WO42− and Al(OH)4−, respectively, in a solution containing 0.5mol/L [W]T and 0.1mol/L [Al]T in the pH range of 11.5–14.0. The decrease in the pH range to 4.0–11.5 resulted in the precipitation of aluminium as Al(OH)3. The extractant of quaternary ammonium salt has stronger affinity with WO42− than that with Al(OH)4−. The solvent extraction of tungsten in alkaline medium using the extractant with the HCO3− form would result in the decrease of the raffinate pH and the formation of Al(OH)3 precipitate at pH <11.5, causing the emulsion in the solvent extraction process. By controlling the raffinate pH higher than 11.5, the extractions of tungsten and aluminium were 99.2% and 1.2%, respectively after a 12-stage counter-current extraction, resulting in a separation factor βAlWO3>9800. This indicates that the efficient separation of tungsten and aluminium can be achieved in by direct solvent extraction in alkaline medium.

Sinapis Alba Extract as Green Corrosion Inhibitor for Aluminum in Alkaline Media

Sinapis Alba Extract as Green Corrosion Inhibitor for Aluminum in Alkaline Media

Investigation of Corrosion Inhibitors and Inhibitive Effect of Some Novel Organic Dyes on the Corrosion of 2S Aluminum in Alkaline Media

not Available.

A Green Pathways: Investigation of Corrosion Inhibitors and Inhibitive Effect of Some Novel Organic Dyes on the Corrosion of 2S Aluminum in Alkaline Media

not Available.

10.1007/s11178-008-2014-7

Reduction of 4-nitro-1-ethyl-1H-1,2,3-triazole with aluminum in alkaline medium resulted in a syn-isomer of 1,2-bis(1-ethyl-1H-1,2,3-triazol-4-yl)diazene 1-oxide. The latter according to the data of X-ray diffraction analysis existed in the crystal as the most stable s-cis,s-trans-conformer, and in solution, as showed NMR data, as a mixture of s-cis,s-trans- and s-trans,s-trans-conformers. The data of quantum-chemical calculations are in agreement with the results of the structural studies.

Understanding aluminum behaviour in aqueous alkaline solution using coupled techniques: Part II: Acoustic emission study

This work focuses on the behaviour of pure aluminum in alkaline media, by coupling both acoustic emission (AE) and direct hydrogen voltammetry to electrochemistry. We notably monitored, recorded and analyzed the acoustic emission activity generated by the aluminum electrode as a function of its polarization during a linear sweep voltammetry (from anodic to cathodic potentials) on pure aluminum in 4 M aqueous potassium hydroxide solution. Such in situ coupling of electrochemistry and acoustic emission shows a perfect correlation between the two signals. After careful analysis of the AE signal using a statistical treatment, and based on five relevant AE parameters (rise time, duration, amplitude, absolute energy, maximum frequency), we could separate various groups of AE signals occurring at the aluminum electrode. We further linked them to the different (and possibly concomitant) electrochemical phenomena, which are taking place upon polarization of the aluminum electrode in strong alkaline medium. First, we confirmed that hydrogen evolution initiates for potentials positive to aluminum open circuit potential in 4 M potassium hydroxide solution; such small but non-negligible hydrogen production occurs in parallel to aluminum oxidation. Second, aluminum oxides are present only around the open circuit potential; whereas they are eroded for high aluminum oxidation potentials, they are flaked off at high hydrogen evolution potentials. Such latter process is probably accelerated by the hydrogen evolution-induced alkalization of the electrolyte. Third, two modes of hydrogen evolution are recorded: one on the oxide, the other one on bare aluminum, the latter being the most efficient. This strong hydrogen evolution at very low electrode potential probably assists the removal of the brittle residual oxide/passive film present on aluminum (which we denote as hydrogen-assisted aluminum exfoliation corrosion), therefore causing the rapid erosion of the aluminum electrode. As a result, aluminum is never in immunity conditions in strong alkaline medium.

Synergistic effect of halide ions and polyethylene glycol on the corrosion inhibition of aluminium in alkaline medium

AbstractThe corrosion inhibition of aluminium in alkaline medium was studied at 30 and 40°C in the presence of polyethylene glycol (PEG) using gravimetric (weight loss) and thermometric techniques. The effect of halides (KCl, KBr, and KI) on the inhibitory action of PEG was also studied. It was found that PEG acted as inhibitor for aluminium corrosion in the alkaline medium. Inhibition efficiency increased with increasing inhibitor concentration. An increase in temperature led to increase in both the corrosion rate and inhibition efficiency in the absence and presence of inhibitor and halides. Phenomenon of chemical adsorption mechanism is proposed from the values of Ea, Qads, and ΔG obtained. The adsorption of PEG on the surface of aluminium was found to obey Flory–Huggins and Temkin adsorption isotherms. The synergism parameter, S1 evaluated was found to be greater than unity indicating that the enhanced inhibition efficiency caused by the addition of halides is synergistic in nature. The inhibition efficiency, surface coverage and synergism parameter increased in the order; I−&gt; Br−&gt; Cl− showing that a joint adsorption of PEG and halide ions on aluminium plays a significant role in the adsorption process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Synergistic Influence of Gum Arabic and Iodide Ion on the Corrosion Inhibition of Aluminium in Alkaline Medium

The effect of iodide ion on the corrosion inhibition of aluminium in NaOH in the presence of Gum Arabic (GA) was studied using weight loss and hydrogen evolution techniques at 303 and 313 K. The results obtained showed that inhibition efficiency increased with increasing GA concentration. The inhibiting action of GA was considerably enhanced by the addition of KI. The adsorption of KI, GA alone and in combination with iodide ion was found to obey Temkin adsorption isotherm. The inhibiting effect of GA and (GA+KI) increased with increase in temperature of the corrosion medium, indicating chemical adsorption mechanism. Synergism parameter evaluated was found to be greater than unity for the different concentrations of GA, which shows that the enhanced inhibition of GA caused by the addition of iodide ion is due to synergistic effect. It could be deduced from the thermodynamic parameters obtained that adsorption of GA alone and in combination with KI onto the metal surface is spontaneous.

Ipomoea Involcrata as an Ecofriendly Inhibitor for Aluminium in Alkaline Medium

The corrosion inhibition of aluminium by Ipomoea involcrata (IP) in 1 M NaOH was rapidly assessed using the gasometric technique at 30 and 60 o C . Results obtained showed that Ipomoea involcrata acts as an inhibitor for aluminium corrosion in 1 M NaOH. Inhibition efficiency increased with increase in concentration of IP up to 55.0 % at 50 v/v% and decreased with increase in temperature. The adsorption of IP was in accord with Langmuir adsorption isotherm at the studied temperatures. A mechanism of physical adsorption is proposed from the calculated values of a E , ads Q and ads G Δ .

Structure of the molecule of 1,2-Bis(1-ethyl-1H-1,2,3-triazol-4-yl)diazene 1-oxide in the crystal and in solutions

Reduction of 4-nitro-1-ethyl-1H-1,2,3-triazole with aluminum in alkaline medium resulted in a syn-isomer of 1,2-bis(1-ethyl-1H-1,2,3-triazol-4-yl)diazene 1-oxide. The latter according to the data of X-ray diffraction analysis existed in the crystal as the most stable s-cis,s-trans-conformer, and in solution, as showed NMR data, as a mixture of s-cis,s-trans- and s-trans,s-trans-conformers. The data of quantum-chemical calculations are in agreement with the results of the structural studies.

Corrosion control of phenylthiourea polymers on aluminium in alkaline medium

AbstractSimple phenylthiourea compounds are known for their high solubility in alkaline medium and for good corrosion control. The monomer N‐(4‐hydroxy‐3‐methoxybenzal)‐N′‐(4′‐hydroxyphenyl) thiourea was condensed with pimeloylchloride and azeloylchloride through inter‐facial polycondensation method to synthesize the polymers. The polymers were dissolved in 2 N sodium hydroxide and their corrosion controlling efficiency on aluminium was studied through AC impedance and potentiodynamic polarization methods.

Effect of halide ions on the corrosion inhibition of aluminium in alkaline medium using polyvinyl alcohol

AbstractThe corrosion inhibition of aluminum in NaOH in the presence of polyvinyl alcohol (PVA) at 30 and 40°C and the effect of addition of halides (KCl, KBr, KI) were studied using weight loss and hydrogen evolution methods. Results obtained showed that PVA acts as a corrosion inhibitor in the alkaline environment. The inhibition efficiency increased with increase in concentration of PVA and synergistically increased on the addition of the halides but however decreased with rise in temperature. The phenomenon of physical adsorption is proposed from the obtained Ea and Qads values. PVA was found to obey Freundlich and Frumkin adsorption isotherms. The increase in inhibition efficiency I (%), surface coverage θ values as well as synergistic parameter, SI were found to be in the order I− &gt; Br− &gt; Cl−, which clearly indicates that the radii and electronegativity of the halides play a significant role in the adsorption process. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2810–2816, 2007

Gum arabic as a potential corrosion inhibitor for aluminium in alkaline medium and its adsorption characteristics

PurposeTo investigate the inhibitive effect of gum arabic (GA) for the corrosion of aluminium in alkaline (NaOH) medium and determine its adsorption characteristics. The present work is another trial to find a cheap and environmentally safe inhibitor for aluminium corrosion.Design/methodology/approachThe inhibition efficiency (%I) has been evaluated using the hydrogen evolution (via the gasometric assembly) and the thermometric methods at 30 and 40°C. The concentrations of GA (inhibitor) used were 0.1‐0.5 g/l and the concentrations of NaOH (the corrodent) were 0.1‐2.5 M. The mechanism of adsorption inhibition and type of adsorption isotherms were proposed from the trend of inhibition efficiency with temperature, Ea, ΔGads and Qads values.FindingsGA inhibited the corrosion of aluminium in NaOH solutions. The inhibition efficiency increased with increase in GA concentration and with increase in temperature. Phenomenon of chemical adsorption is proposed for the inhibition and the process followed the Langmuir and Freundlich adsorption isotherms. The results obtained in this study for the %I were comparable for the two methods used and were corroborated by kinetic and thermodynamic parameters evaluated from the experimental data.Research limitations/implicationsFurther investigations involving electrochemical studies such as polarization method will enlighten more on the mechanistic aspect of the corrosion inhibition.Originality/valueThis paper provides new information on the possible application of GA as an environmentally friendly corrosion inhibitor even in highly aggressive alkaline environments. It has not been published elsewhere.