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1 – 10 of 659A.K. Mohamed, K.M. Ibrahim and M.N.H. Moussa
The corrosion behaviour of iron in M HNO3 containing furfural hydrazone derivatives was studied by electro‐chemical, polarographic and scanning electron microscopy measurements…
Abstract
The corrosion behaviour of iron in M HNO3 containing furfural hydrazone derivatives was studied by electro‐chemical, polarographic and scanning electron microscopy measurements. Polarization data indicates that all inhibitors tested were of a mixed type, affecting both the cathodic and anodic processes. The inhibition efficiency of the additives increases in the order I<II<III<IV<V. It was found that the compounds under consideration are adsorbed on the iron surface. The degree of surface coverage is influenced by the presence of functional groups and interaction between adsorbed molecules. Within the given homologous series the contribution of the functional group to adsorption increases with the length of the chain.
S.M. Hassan, M.N. Moussa, M.M. El‐Tagoury and A.A. Radi
The inhibition of aluminium corrosion in solutions of hydrochloric acid or sodium hydroxide has been studied using weight‐loss and hydrogen evolution methods. Benzoic acid and its…
Abstract
The inhibition of aluminium corrosion in solutions of hydrochloric acid or sodium hydroxide has been studied using weight‐loss and hydrogen evolution methods. Benzoic acid and its derivatives inhibit acidic and alkaline corrosion effectively. The efficiency of inhibitors increases in the order: benzamide < benzaldehyde < acetophenone < benzoic acid < benzophenone (100%). The inhibition efficiency of acid anhydrides follows the sequence: pyromellitic > naphthalic > trimellitic. Inhibition takes place through adsorption by a one‐step process with greater efficiency in alkaline than in acidic methanolic solutions.
M.N. Moussa, M.M. El‐Tagoury, A.A. Radi and S.M. Hassan
Inhibition of carboxylic acids of aluminium corrosion in hydrochloric acid and sodium hydroxide solutions has been studied using weight‐loss and hydrogen evolution methods. The…
Abstract
Inhibition of carboxylic acids of aluminium corrosion in hydrochloric acid and sodium hydroxide solutions has been studied using weight‐loss and hydrogen evolution methods. The order of inhibition action of aromatic acids depends on the number and position of the carboxylic groups and the other substituents in the benzene ring. Increase of the chain length increases the inhibiting power of aliphatic acids. The inhibition efficiency in NaOH is higher than that in HCI solutions. The action of inhibition was discussed in terms of the chemical structure of the inhibitors.
Awad I. Ahmed, S.N. Basahel and R.M. Khalil Chemistry
The inhibitive effect of some morpholine and thiosemicarbazide derivatives on the dissolution of aluminium in 2M HCI has been investigated by using thermometric, weight loss and…
Abstract
The inhibitive effect of some morpholine and thiosemicarbazide derivatives on the dissolution of aluminium in 2M HCI has been investigated by using thermometric, weight loss and hydrogen evolution techniques. The effect of the inhibitors on the protection efficiency and the corrosion rate were determined at various inhibitor concentrations and temperatures. It was observed that the percentage inhibition of aluminium increases with the increase of inhibitor concentration and decreases with rise of reaction temperature. Retardation of dissolution is due to weak adsorption of the additives on the metal surface. The order of inhibition efficiency of the inhibitors used depends on the number of adsorption sites in the molecule, their charge density and molecular size.
M.M. El‐Tagouri, M.R. Mostafa, H.M. Abu El‐Nader and G.M. Abu El‐Reash
The efficiency of some 2‐heterocarboxaldehyde‐2′‐pyridyl‐hydrazones as inhibitors for the acid dissolution of Al was studied by mass loss, hydrogen evolution and polarization…
Abstract
The efficiency of some 2‐heterocarboxaldehyde‐2′‐pyridyl‐hydrazones as inhibitors for the acid dissolution of Al was studied by mass loss, hydrogen evolution and polarization measurement techniques. The corrosion rate was measured in 2M HCI at different temperature and concentrations; maximum percentage protection (85%) was obtained at 103M for the compound containing oxygen atom. The activation energies were calculated for all the additives used. The rate constant decreases as the inhibition efficiency increases. The results show that the studied materials influencing both the cathodic and anodic process. The mechanism of inhibition was proposed on the basis of the formation of a protective monolayer by the inhibitors molecules on the metal surface according to Langmuir isotherm.
Y.A. Elewady, M.M. El‐Tagoury, G.E. Bekheit and S.M. Hassan
The effect of some pyrazoline derivatives as inhibitors on the dissolution of A1 in 2 mol.L−1 HC1 has been studied by weight‐loss, galvanostatic polarization, polarographic and…
Abstract
The effect of some pyrazoline derivatives as inhibitors on the dissolution of A1 in 2 mol.L−1 HC1 has been studied by weight‐loss, galvanostatic polarization, polarographic and scanning electron microscopy methods. Additions of Cu2+ Co2+ or Ni2+ ions increases the efficiency of the inhibitors.
Samy Shaban, Abd Elaziz Fouda, Mohamed Elmorsi, Tarek Fayed and Omar Azazy
The purpose of this study is to inspect the corrosion inhibition of API N80 steel pipelines in uninhibited solution and inhibited with a synthesized surfactant compound [N…
Abstract
Purpose
The purpose of this study is to inspect the corrosion inhibition of API N80 steel pipelines in uninhibited solution and inhibited with a synthesized surfactant compound [N-(3-(dimethyl octyl ammonio) propyl) palmitamide bromide] (DMDPP), which is prepared through a simple and applicable method.
Design/methodology/approach
Weight loss was inspected at five different temperatures of 25°C, 30°C, 40°C, 50°C and 60°C Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation were used at room temperature. Density functional theory was used to study the relation between the molecular structure and inhibition theoretically.
Findings
Adsorption of the prepared DMDPP fits the Langmuir isotherm model. The inhibition efficiency of the prepared DMDPP amphipathic inhibitor is directly proportional to temperature increase. Polarization results reveal that the investigated DMDPP amphipathic compound behaves as a mixed-type inhibitor. EIS spectra produced one individual capacitive loop.
Originality/value
The originality is the preparation of cationic surfactants through a simple method, which can be used as corrosion inhibitors in oil production. The synthesized inhibitors were prepared from low-price materials. The work studied the behavior of the synthesized surfactants in inhibiting the corrosion of the steel in an acidic medium. Electrochemical and theoretical studies were presented, besides gravimetric and surface examination.
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A.S. Fouda, Y.A. El‐Ewady, O.M. Abo‐El‐Enien and F.A. Agizah
The purpose of this paper is to show the effect of cinnamoylmalononitrile (CMN) compounds on the corrosion inhibition of carbon steel in HCl and the effect of some substituent…
Abstract
Purpose
The purpose of this paper is to show the effect of cinnamoylmalononitrile (CMN) compounds on the corrosion inhibition of carbon steel in HCl and the effect of some substituent groups on the corrosion inhibition.
Design/methodology/approach
Several papers have been published (1900‐1999), which aimed to investigate and explain the effect of organic compounds on the corrosion inhibition process. Two methods were used to determine the corrosion rate, weight loss and galvanostatic polarization. Additionally, the effects of temperature and concentration of the inhibitors were studied. The thermodynamic parameters for the process were computed and discussed.
Findings
The paper finds that surface analytical techniques such as X‐ray photoelectron spectroscopy and Auger spectroscopy can shed more light, on the mechanism of corrosion inhibition.
Research limitations/implications
The use of donating and withdrawing groups will improve understanding of the mechanisms of corrosion and inhibition. However, the paper does not use the technique of impedance measurement for comparison purposes.
Practical implications
Other steel alloys and compounds with large or small molecular weights can be used for comparison.
Originality/value
The use of CMN compounds as corrosion inhibitors for carbon steel in HCl provides more information on carbon steel corrosion for academic and starting researchers.
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Bahram Ramezanzadeh, Milad Mehdipour, S.Y. Arman and M. Ramezanzadeh
This study attempts to investigate corrosion inhibition properties of 1H-benzimidazole (B) and 1H-benzotriazole (BTA) on aluminum in 0.25 M HCl solution at different…
Abstract
Purpose
This study attempts to investigate corrosion inhibition properties of 1H-benzimidazole (B) and 1H-benzotriazole (BTA) on aluminum in 0.25 M HCl solution at different concentrations.
Design/methodology/approach
To this end, electrochemical techniques including electrochemical noise (EN), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used.
Findings
Results showed a greater corrosion inhibition efficiency of BTA than B on aluminum in HCl solution. BTA showed greater tendency to adsorption on the metal surface than B because of the inclusion of three nitrogen atoms.
Originality/value
The novelty of this work is comparing EN data with EIS and potentiodynamic polarization parameters.
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The purpose of this paper is to assess the viability of the scholarly search engine Microsoft Academic (MA) as a citation source for evaluating/ranking marketing journals.
Abstract
Purpose
The purpose of this paper is to assess the viability of the scholarly search engine Microsoft Academic (MA) as a citation source for evaluating/ranking marketing journals.
Design/methodology/approach
This study performs a comparison between MA and Google Scholar (GS) in terms of journal coverage, h-index values and journal rankings.
Findings
Findings indicate that: MA (vs GS) covers 96.80 percent (vs 97.87 percent) of the assessed 94 marketing-focused journals; the MA-based h-index exhibits values that are 35.45 percent lower than the GS-based h-index; and that the MA-based ranking and the GS-based ranking are highly consistent. Based on these findings, MA seems to constitute a rather viable citation source for assessing a marketing journal’s impact.
Research limitations/implications
This study focuses on one discipline, that is, marketing.
Originality/value
This study identifies some issues that would need to be fixed by the MA’s development team. It recommends some further enhancements with respect to journal title entry, publication year allocation and field classification. It also provides two up-to-date rankings for more than 90 marketing-focused journals based on actual cites (October 2018) of articles published between 2013 and 2017.
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