P. Satyabama, Susai Rajendran and Tuan Anh Nguyen
This paper aims to evaluate the inhibition efficiency (IE) of oxalate ions in controlling corrosion of aluminum at pH 10.
Abstract
Purpose
This paper aims to evaluate the inhibition efficiency (IE) of oxalate ions in controlling corrosion of aluminum at pH 10.
Design/methodology/approach
The IE has been determined by the classical weight loss method. The corrosion behavior of aluminum was investigated by using potentiodynamic polarization and electrochemical impedance measurements. Ultra violet (UV)-visible and Fluorescence spectra have been used to analyze the film formed on the aluminum surface after immersion.
Findings
The maximum IE was 88 per cent, which was offered by a mixture of 250 ppm oxalate ions and 50 ppm [Zn2+]. Potentiodynamic polarization data revealed that the protective film was formed on the metal surface. UV-visible and Fluorescence spectra indicated the presence of Al3+−oxalate complex in the protective film formed on aluminum substrate after immersion in [OX]/[Zn2+] solution.
Originality/value
The findings of this work shed more light on the corrosion inhibition of aluminum by oxalate self-assembling monolayers.
Details
Keywords
Okechukwu Okechukwu Onukwuli, Benson Chinweuba Udeh, Monday Omotioma and Ikechukwu Abuchi Nnanwube
The purpose of this study was to investigate cimetidine as corrosion inhibitor of aluminium in hydrochloric acid medium.
Abstract
Purpose
The purpose of this study was to investigate cimetidine as corrosion inhibitor of aluminium in hydrochloric acid medium.
Design/methodology/approach
Cimetidine was characterized by gas chromatography mass spectrophotometer and Fourier transform infrared spectroscopy to determine its chemical composition and functional groups, respectively. Gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic techniques were used in the corrosion inhibition process. Thermodynamic and adsorption parameters were evaluated. And response surface methodology was used to optimize the corrosion inhibition process.
Findings
Analysis of the results revealed that major constituents of cimetidine include metronidazole, n-hexadecanoic acid cyclohexane and methyl ester. It has C-H stretch, C = N stretch, CH3C-H bend, ring C = C stretch, -C-O-O stretch, N-H bend, C-O stretch and C-H bend as predominant functional groups. Adsorption of molecules of the inhibitor on the aluminium surface was spontaneous, and it followed mechanism of physical adsorption. Response surface methodology revealed that quadratic model adequately described the inhibition efficiency of cimetidine as function of inhibitor concentration, temperature and time. Chemical and electrochemical results are in agreement that the cimetidine is a viable corrosion inhibitor. Cimetidine was revealed as mixed-type inhibitor because it controlled both cathodic and anodic reactions.
Originality/value
Empirical and optimization studies of cimetidine drug as corrosion inhibitor of aluminium in hydrochloric acid medium were carried out. The research results can provide the basis for deploying drugs (with mucosal protective and antacid properties) for corrosion control of metallic structures.
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Keywords
Justin C Emereole, Chigoziri N Njoku, Alexander I Ikeuba, Ifenyinwa C Ekeke, Emmanuel Yakubu, Ogbonna C Nkuzinna, Nnamdi A Nnodum and Madueke S Nwakaudu
This study aims to develop eco-friendly corrosion inhibitors for aluminum in acidic media by evaluating the corrosion inhibition properties of corn leaf extract (CLE) using…
Abstract
Purpose
This study aims to develop eco-friendly corrosion inhibitors for aluminum in acidic media by evaluating the corrosion inhibition properties of corn leaf extract (CLE) using response surface methodology (RSM) and experiments.
Design/methodology/approach
The RSM was combined with experiments to evaluate the corrosion inhibition properties of CLE on aluminum in acid media.
Findings
The effectiveness of the inhibition increased with increasing inhibitor concentration and time but decreased with increasing temperature. The corrosion inhibition mechanism revealed the corrosion process is spontaneous exothermic physical adsorption. Thermodynamic parameters revealed an activation energy between 32.1 and 24.7 kJ/mol, energy of adsorption between −14.53 and −65.07 and Gibbs free energy of −10.12 kJ/mol which indicated the CLE exothermically spontaneously physisorbed. A model was generated to estimate the effect of the process parameters (inhibitor concentration, reaction time and temperature) using the RSM. Optimization of the process factors was also carried out using the RSM. The percentage inhibition efficiency obtained experimentally (85.61%) was closely comparable to 84.89% obtained by the theoretical technique (RSM). The SEM observations of the inhibited and uninhibited Al samples demonstrated that CLE is an effective corrosion inhibitor for aluminum in acid media.
Originality/value
Results herein provide novel information on the possible application of CLEs as effective eco-friendly corrosion inhibitors.