The Effect of Corrosion Inhibitor in Hydrofluoric Acid Medium

2013 ◽  
Vol 750-752 ◽  
pp. 2258-2262 ◽  
Author(s):  
Wei Ming Wu ◽  
Ding Li ◽  
Hai Yan Du

The experiments were done to find some good corrosion inhibitors for mild steel in 5% HF solution by the method of weight loss and electrochemistry including polarization curves and electrochemical impedance spectroscopy (EIS). Results show that the thiourea, potassium thiocyanate, and hexamethylenetetramine have good inhibition effect for mild steel in 5% HF solution, especially potassium thiocyanate and thiourea. Their corrosion resistance was greatly enhanced in the presence of tested inhibitor. Thiourea is an anodic type inhibitor and its inhibition efficiencies up to 99.88% can be obtained. Equivalent circuit of the investigated system was suggested.

2017 ◽  
Vol 64 (1) ◽  
pp. 23-35 ◽  
Author(s):  
Mohammed Elalaoui Belghiti ◽  
Ayssar Nahlé ◽  
Abdeslam Ansari ◽  
Yasser Karzazi ◽  
S. Tighadouini ◽  
...  

Purpose This paper aims to study the inhibition effect of 2-pyridinealdazine on the corrosion of mild steel in an acidic medium. The inhibition effect was studied using weight loss, electrochemical impedance spectroscopy, and Tafel polarization measurements. Design/methodology/approach Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy, X-ray diffraction and spectral and conformational isomers analysis of A (E-PAA) and B (Z-PAA) were performed were investigated. Findings 2-pyridinealdazine (PAA) acts as a good inhibitor for the corrosion of steel in 2.0 M H3PO4. The inhibition efficiency increases with an increase in inhibitor concentration but decreases with an increase in temperature. Originality/value This paper is intended to be added to the family of azines which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.


RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25314-25333
Author(s):  
Mai A. Khaled ◽  
Mohamed A. Ismail ◽  
Ahmed. A. El-Hossiany ◽  
Abd El-Aziz S. Fouda

This study targets the investigation of three pyrimidine derivatives (MA-1230, MA-1231, MA-1232) for the prevention of corrosion on copper in 1 M HNO3via weight loss (WL), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques.


Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2611
Author(s):  
Esther Udabe ◽  
Anthony Sommers ◽  
Maria Forsyth ◽  
David Mecerreyes

Chromate free corrosion inhibitors are searched for to mitigate the economic loss caused by mid-steel corrosion. Here, we show metal-free organic inhibitors having free coumarate anions that can be used either as direct corrosion inhibitors or incorporated into a polymer coating obtained by UV-curing. Four different ionic liquid monomers and polymer coatings with hexoxycoumarate anion and different polymerizable counter cations were investigated. Potentiodynamic polarization, electrochemical impedance spectroscopy, and surface analyses have verified their corrosion inhibition performance on a mild steel AS1020 surface. In the case of the coumarate ionic liquid monomers, the most promising inhibitor is the one coupled with the ammonium cation, showing an inhibition efficiency of 99.1% in solution followed by the imidazolium, pyridinium, and anilinium. Next, the ionic liquid monomers were covalently integrated into an acrylic polymer coating by UV-photopolymerization. In this case, the barrier effect of the polymer coating is combined with the corrosion inhibitor effect of the pendant coumarate anion. Here, the best polymer coatings are those containing 20% imidazolium and pyridinium cations, presenting a greater impedance in the EIS (Electrochemical Impedance Spectroscopy) measurements and less evidence of corrosion in the scribe tests. This article shows that the cationic moiety of coumarate based ionic liquids and poly(ionic liquid)s has a significant effect on their excellent corrosion inhibition properties for a mild steel surface exposed to aqueous chloride solutions.


2009 ◽  
Vol 6 (s1) ◽  
pp. S189-S194 ◽  
Author(s):  
N. S. Patel ◽  
S. Jauhari ◽  
G. N. Mehta

Extract ofFicus exasperataleaves was investigated as corrosion inhibitor of mild steel in 1 N H2SO4using conventional weight loss, electrochemical polarizations, electrochemical impedance spectroscopy and scanning electron microscopic studies. The weight loss results showed that the extract ofFicus exasperatais excellent corrosion inhibitor. Electrochemical polarizations data revealed the mixed mode of inhibition. The results of electrochemical impedance spectroscopy shows that the change in the impedance parameters, charge transfer resistance and double layer capacitance, with the change in concentration of the extract is due to the adsorption of active molecules leading to the formation of a protective layer on the surface of mild steel. Scanning electron microscopic studies provided the confirmatory evidence of improved surface condition, due to the adsorption, for the corrosion protection.


2017 ◽  
Vol 893 ◽  
pp. 313-317
Author(s):  
Jin Hu Sun ◽  
Hui Li ◽  
Qing Dong Zhong ◽  
Chen Xiao ◽  
Zhe Rui Huang ◽  
...  

Cu/Zn/Cu multilayer coatings were prepared on mild steel substrates by dual bath technique in order to improve the corrosion resistance of mild steel in seawater. The microstructures of the coated substrates and its resistance to corrosion in simulated seawater were evaluated by scanning electron microscopy (SEM), the brine immersion test and electrochemical impedance spectroscopy (EIS). Salt water immersion test results show that the Cu/Zn/Cu multilayer coatings exhibited the highest corrosion resistance. The red rust spot appeared on the coating surface for the first time when the time of the coating soaked in salt water reached 2520h. The trend of the impedance variation reflected by the electrochemical impedance spectroscopy was the same as the change tendency of corrosion resistance was analyzed by the salt water immersion test. The results of SEM showed that the layer of copper were deposited by round cell structure, the middle layer of zinc coating was flat and compact.


Author(s):  
K.K. Taha ◽  
Musa E. Mohamed ◽  
S.A. Khalil ◽  
S.A. Talab

Brass as an alloy composed mainly of copper is great industrial uses such as heat exchangers and similar other facility due to its good thermal properties. Due to the presence of the considerable ratio of zinc the alloy suffers from zinc dissolution or dezincification. Dezincification rate increases with the increase in the ratio of zinc in the alloy. In this study benzothiazole (BTH) and its substituent’s 2-methylbenzothiazole (MeBTH), 2-aminobenzothiazole (ABTH), 2-mercaptobenzothiazole (MBTH) and 2-phenylbenzothiazole (PhBTH) have been used as corrosion inhibitors for α-brass in stirred 0.1 M HClO4. The methods of investigation include weight loss, Tafel and linear polarizations and electrochemical impedance spectroscopy. The order of inhibition efficiency (%E) was calculated and the values obtained has indicated the sequence of inhibition efficiency was found to be BTH < MeBTH < ABTH < PhBTH < MBTH. The calculated values of thermodynamic parameters support this order. The inhibitors were found to suppress the corrosion rate by the formation of films which were identified by IR, SEM and EDAX techniques.


2011 ◽  
Vol 311-313 ◽  
pp. 657-661
Author(s):  
Xiao Hong Huang ◽  
Sheng Tao Zhang ◽  
Lian Yue Hu

This paper investigates the Isoniazid as chemical corrosion inhibitors for brass in 3.0% NaCl solution of different pH, employing polarization curves, electrochemical impedance spectroscopy(EIS), weight loss, and SEM. It is found that the inhibition efficiency of Isoniazid enhances with the increasing of the solution pH, from about 71% at pH 6.5 to 92% at pH 10.5. This improvement is attributed to the stronger adsorption of Isoniazid in alkaline solution, to prevent the occuring of the corrosion reaction of brass.


2017 ◽  
Vol 64 (5) ◽  
pp. 563-572 ◽  
Author(s):  
Asmae Bouoidina ◽  
Mehdi Chaouch ◽  
Abdelfattah Abdellaoui ◽  
Amal Lahkimi ◽  
Belkheir Hammouti ◽  
...  

Purpose The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance spectroscopy and Tafel polarization, as well as the surface morphology of the mild steel. Design/methodology/approach Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy studies and gas chromatography/mass spectrometry and scanning electron microscopy analysis of FVS extract were performed. Findings FVS extract acts as a good inhibitor for the corrosion of mild steel in 1.0 M HCl. The inhibition efficiency increases with the increase in inhibitor concentration but decreases with the increase of temperature. Practical implications FVS extract was observed to play an important role in the corrosion inhibition of mild steel in acidic solution. Originality/value This paper is intended to be added to the family of green inhibitors which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.


2021 ◽  
Vol 25 (8) ◽  
pp. 1441-1448
Author(s):  
B.U. Ugi ◽  
V.M. Bassey ◽  
M.E. Obeten ◽  
S.A. Adalikwu ◽  
E.C. Omaliko ◽  
...  

The study on the action of Acetylcholine and Rivastigmine as Corrosion Inhibitors of Cu – Sn - Zn – Pb Alloy in Hydrochloric Acid Environment was carried out using density functional theory, electrochemical impedance spectroscopy, Potentiodynamic polarization, Scanning electron microscopy and weight loss. The result revealed that both Acetylcholine and Rivastigmine expired drugs were good inhibitors of Cu – Sn - Zn – Pb Alloy in Hydrochloric Acid Environment. This was confirmed from results of weight loss (99.1 % and 95.0 %), electrochemical impedance spectroscopy (EIS) (92.5 % and 91.8 %), and Potentiodynamic polarization (97.4 % and 87.1 %). Both inhibitors were able to increase the charge transfer resistance and corrosion current densities of the electrical solution and reduce the double layer capacitance of the metal – solution interface. Inhibition was as a result of adsorption of inhibitor molecules on the Cu – Sn - Zn – Pb surface. Thermodynamically, inhibitors showed greater stability on metal surface, spontaneous in the forward direction and reduction in level of disorderliness. Inhibitors demonstrated a mixed type inhibition while physical adsorption mechanism was proposed for the inhibitor – metal interaction. Langmuir adsorption isotherm was obeyed as data fitted adequately to the isotherm and regression coefficient was approximately unity. A monolayer adsorption was deduces.


Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 675 ◽  
Author(s):  
Mohammad A. Jafar Mazumder

The zwitterionic monomers, N,N’-diallylamino propanephosphonate and amino acid residual N,N’-diallyl-l-methionine hydrochloride were synthesized, with excellent yields. These monomers were utilized in the preparation of zwitterionic homo and co-cyclopolymers 5–7 in aqueous solution using 2,2′-azobis (2-methylpropionamidine) dihydrochloride as an initiator. The polymers were characterized by FT-IR, NMR, and TGA. The performance of these synthesized polymers on mild steel in acidic solution was investigated by gravimetric method, Tafel extrapolation, linear polarization resistance, and electrochemical impedance spectroscopy. At 313 K, the maximum inhibition efficiencies of corrosion inhibitors 5–7 at 4.50 × 10−4 mol L−1 were found to be 85.2%, 83.3%, and 99.5%, respectively. The inhibition efficiencies obtained from gravimetric weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy measurements were in good agreement. Different adsorption isotherms were also explored to find the best fit, and found to obey Langmuir adsorption isotherm. The thermodynamic parameters, such as activation energy (Ea), standard enthalpy of activation (ΔH*), standard entropy of activation (ΔS*), adsorption–desorption equilibrium constant (Kads), and standard free energy of adsorption (ΔGoads), were determined. Electrochemical data indicated that the zwitterionic copolymer 7 acts as a mixed type inhibitor under the influence of anodic control. The surface morphology of mild steel corrosion was evaluated without and with corrosion inhibitors by AFM, SEM-EDX, and XPS, which confirmed the adsorption of inhibitor molecules on the metal surface.


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