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1 – 2 of 2Nobl F. El Boraei, Shimaa Abdel Halim and Magdy A.M. Ibrahim
The purpose of this paper is to test the Natural Kermes dye (NKD) as a cheap and stable corrosion inhibitor for mild steel in 1.0 M HCl and its adsorption mechanism on the steel…
Abstract
Purpose
The purpose of this paper is to test the Natural Kermes dye (NKD) as a cheap and stable corrosion inhibitor for mild steel in 1.0 M HCl and its adsorption mechanism on the steel surface.
Design/methodology/approach
The inhibition action of NKD was studied using AC impedance, potentiodynamic polarization, scanning electron microscope (SEM) and UV-visible spectra techniques complemented with quantum study.
Findings
Here, the authors show that addition of NKD inhibits effectively the corrosion of steel in HCl solution via its adsorption on the steel surface. The inhibition efficiency of NKD increases with increase in its concentration and decreases with temperature. Potentiodynamic results revealed that NKD acts as a mixed–type inhibitor. Thermodynamic parameters for corrosion and adsorption process were obtained from the experimental data. Moreover, the experimental inhibition efficiencies were correlated with the electronic properties of NKD using density functional theory.
Originality/value
To the best of the authors’ knowledge, this is the first report showing the effect of NKD on the corrosion inhibition of steel.
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Keywords
Nobl Foad El Boraei, Sayed S. Abd El Rehim and Hamdy H. Hassan
The purpose of this paper is to study the electrochemical behavior of Sn electrode in Na2B2O7 solutions in the absence and presence of NaNO3 as a pitting corrosion agent.
Abstract
Purpose
The purpose of this paper is to study the electrochemical behavior of Sn electrode in Na2B2O7 solutions in the absence and presence of NaNO3 as a pitting corrosion agent.
Design/methodology/approach
The electrochemical behavior of Sn electrode was studied by using cyclic voltammetry and potentiodynamic polarization measurements and complemented with scanning electron microscopy examinations.
Findings
This paper shows that in the absence of NO3 − ions, the anodic polarization of Sn electrode exhibits active/passive transition. Addition of various concentrations of NO3 − anions to the borate solution enhances active anodic dissolution and tends to break down the passive oxide film at a certain pitting potential. The pitting potential, and hence the pitting corrosion resistance, decreases with increasing NO3-ion concentration and temperature but increases with scan rate and repetitive cycling. Addition of CrO42−, WO42− or MoO42− oxyanions to the borate nitrate solution inhibits the pitting corrosion of Sn.
Originality/value
This is the first study that shows the effect of NO3 − ion as a pitting corrosion agent.
Details