CORROSION INHIBITORY EFFECT OF FEW PIPERIDIN-4-ONE OXIMES ON MILD STEEL IN HYDROCHLORIC ACID MEDIUM

2009 ◽  
Vol 16 (01) ◽  
pp. 141-147 ◽  
Author(s):  
A. N. SENTHILKUMAR ◽  
K. THARINI ◽  
M. G. SETHURAMAN

Three piperidin-4-one oxime derivatives viz. 3,5-dimethyl-2,6-diphenyl-piperidin-4-one oxime (DDPO), 3-ethyl-2,6-diphenyl-piperidin-4-one oxime (EDPO), and 1-methyl-3-isopropyl-2, 6-diphenyl-piperidin-4-one oxime (MIDPO) were synthesized. Corrosion inhibiting ability of these compounds in 1 M HCl was studied using weight loss study, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, XRD and SEM with EDS measurements. Weight loss studies revealed that all the three oximes are good corrosion inhibitors. The order of inhibiting ability of these compounds is as follows: DDPO > EDPO > MINDO. Results of the polarization measurement showed that these inhibitors do not alter the mechanism of either hydrogen evolution or mild steel dissolution reaction, proving the mixed mode of inhibition. At constant acid concentration, increase of inhibitor concentration increased the charge transfer resistance (R ct ), complimented with decrease of double layer capacitance (C dl ), thereby indicating the increase of percentage inhibition efficiency. XRD and SEM with EDS analysis provided strong proof for the existence of inhibitor film over the mild steel surface.

2021 ◽  
Vol 33 (12) ◽  
pp. 2953-2964
Author(s):  
Vikas Kalia ◽  
Pradeep Kumar ◽  
Suresh Kumar ◽  
Hariom Dahiya

The corrosion inhibition consequence of 5-(4-aminophenyl)-1,3,4-oxadiazole-2-thiol (APOT) and 5-(4-methylphenyl)-1,3,4-oxadiazole-2-thiol (MPOT) were accomplished by employing weight loss measurement, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization measurement and scanning electron microscope (SEM). An impact of immersion time 12.0 h and different temperatures (298, 308 and 318 K) with solution of 1.0 M HCl, which include various concentration of inhibitor at the corrosion of mild steel were designed. Weight loss measurement showed that with enhancing the concentration of these studied inhibitors the percentage inhibition efficiency (IE%) enhances, but corrosion rate (CR) diminishes while reverse condition in case of temperatures change. The electrochemical impedance spectroscopy examine pointed out that the charge transfer resistance (Rct) values enhances and consequently the double layer capacitance (Cdl) values diminishes with rising each inhibitor concentration in 1.0 M HCl and also there is a formation of adsorption coating at the metal surface. Polarization measurement showed that both APOT and MPOT perform as mixed type corrosion inhibitors. Furthermore, the adsorption behaviour on surface of mild steel for each studied inhibitor results the Langmuir adsorption isotherm. Surface conduct of mild steel also designed through the SEM and energy dispersive X-ray (EDX) analysis and concludes that there is evolution of inhibitive film of APOT and MPOT on the surface of mild steel.


2020 ◽  
Vol 61 (4) ◽  
pp. 286-305
Author(s):  
Ali Adel ◽  
El-Aziz Abd ◽  
Tilp Amal

The impact of Lidocaine as a save corrosion inhibitor for mild steel (MS) in 1M HCl by using weight loss (WL), Hydrogen evaluation (HE), open circuit potential (EO C P), potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS) and Electrochemical frequency modulation (EFM) techniques has been investigated. Weight loss studied at various temperatures between (25-45oC) but Hydrogen evaluation and electrochemical studies at room temperature. The effect of temperature on the inhibition of corrosion has been studied and the thermodynamic activation and adsorption parameters were calculated. The morphology of MS was examined by scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX) technology and atomic force microscopy (AFM). EIS data indicate that in the presence of drug the double layer capacitance was decreased and the charge transfer resistance increased. The adsorption of the Lidocaine on MS surface was found to obey Langmuir adsorption isotherm and elucidate the mechanism of corrosion inhibition. The Lidocaine drug acts as mixed type inhibitor. All surface examination confirms the formation thin film covered the surface of the metal and prevent the surface of the metal from corrosion.


2021 ◽  
Vol 11 (5) ◽  
pp. 13019-13030

The extract of Justicia secunda (JS) leaves was investigated as an eco‐friendly corrosion inhibitor of aluminum in 0.5 M HCl using weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and scanning electron microscopy (SEM) techniques. The inhibitor concentrations used ranged from 50 to 250 ppm at 30, 40, and 50oC. Results show that Justicia secunda acts as a good inhibitor for aluminum. Its efficiency increased with increasing inhibitor concentration but decreased with increasing temperature. Maximum inhibition efficiency as high as 94.3% was found at 30°C for 250 ppm of the inhibitor with the weight loss technique. Tafel polarization results show that the extract acts as a mixed-type inhibitor. The Nyquist plots indicated decreasing double-layer capacitance and increasing charge transfer resistance on increasing JS concentration. The inhibition action occurred through the physical adsorption of the extract on the aluminum surface. The adsorption process was found to follow Langmuir adsorption isotherm. The formation of a protective film on the metal surface was confirmed by scanning electron microscopy.


2019 ◽  
Vol 37 (5) ◽  
pp. 657-678
Author(s):  
Muazzam Ghous Sohail ◽  
Mohammad Salih ◽  
Nasser Al Nuaimi ◽  
Ramazan Kahraman

Purpose The purpose of this paper is to present the results of a two-year long study carried out in order to evaluate the corrosion performance of mild steel bare bars (BB) and epoxy-coated rebar (ECR) in concrete under a simulated harsh environment of chlorides. Design/methodology/approach The blocks are subjected to Southern Exposure testing. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and Tafel plot are performed to measure the polarization resistance and corrosion current densities of these rebars. Knife-peel test was performed to assess the adhesion between epoxy and underlying steel after two years of exposure. Findings Mild steel BB showed a high corrosion current density of 1.24 µA/ cm2 in Tafel plots and a very low polarization resistance of 4.5 kΩ cm2 in LPR technique, whereas very high charge transfer resistance of 1672 and 1675 kΩ cm2 is observed on ECR and ECR with controlled damage (ECRCD), through EIS technique, respectively. EIS is observed to be a suitable tool to detect the defects in epoxy coatings. After two years of immersion in 3.89 percent NaCl− solution, the mild steel BB were severely corroded and a considerable weight loss was observed, whereas under heavy chloride attack, ECR showed no deterioration of epoxy coating and neither any corrosion of underlying steel. Results of this study show that the durability of reinforced concrete (RC) structures with respect to corrosion could be enhanced by using ECR, especially in harsh climatic conditions. Originality/value The corrosion performance of mild steel and ECR in concrete under a simulating splash zone environment is evaluated. EIS was used to evaluate the health of epoxy and corrosion state of underneath steel rebars. EIS was able to detect the defects in epoxy. The durability of RC structures could be enhanced in harsh climate regions by using ECR.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Chikkur B. Pradeep Kumar ◽  
Kikkeri N. Mohana

Achyranthes aspera (AA) extracts were studied as corrosion inhibitor for mild steel (MS) in industrial water medium using mass loss and electrochemical techniques. The results of the study revealed that AA extracts inhibit MS corrosion through adsorption process following Langmuir adsorption isotherm model. The protection efficiency increased with increase in inhibitor concentration and decreased with temperature. The electrochemical impedance spectroscopy (EIS) measurements showed that the charge transfer resistance increases with increase in the concentration of AA extracts. The polarization curves obtained indicate that AA extracts act as mixed type of inhibitor. Scanning electron microscopy (SEM) was used to analyze the surface adsorbed film.


2020 ◽  
Vol 38 (2) ◽  
pp. 137-149
Author(s):  
Mohamed Ouknin ◽  
Abderrahmane Romane ◽  
Jean-Pierre Ponthiaux ◽  
Jean Costa ◽  
Lhou Majidi

AbstractThe inhibition effect of Thymus zygis subsp. gracilis (TZ) on mild steel corrosion in 1 m hydrochloric acid has been investigated by weight loss measurements, surface analysis [scanning electron microscopy (SEM)-energy-dispersive X-ray (EDX), three-dimensional (3D) profilometry, and Fourier transform infrared analysis], potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). Gravimetric results indicate that TZ exhibits good inhibition efficiency of 80.40% attained at 3 g/l. Polarization measurements show that the studied inhibitor is a mixed type. EIS measurements revealed that the charge transfer resistance increases with increasing concentration of TZ, which suggests a Langmuir adsorption isotherm model. Based on SEM-EDX and 3D profilometry, it appears that the surface is remarkably improved in the presence of TZ oil compared to that exposed to the acid medium without TZ oil. From the obtained results, it can be concluded that this oil is a new natural substance that can be used against material corrosion in aggressive medium.


2020 ◽  
Vol 27 (09) ◽  
pp. 1950208
Author(s):  
K. A. KARTHICK ◽  
D. S. BHUVANESHWARI ◽  
D. UMAPATHI ◽  
PANDIAN BOTHI RAJA

Canthium parviflorum leaf extract (CPLE) was utilized for corrosion prevention against mild steel (MS) in 0.5[Formula: see text]mol[Formula: see text]L[Formula: see text] H2SO4 test medium. Standard corrosion measurement techniques (gravimetric and electrochemical) were employed for this purpose. Gravimetric tests clearly confirmed that the prepared CPLE efficiently performs as corrosion inhibitor. Potentiodynamic polarization measurements (PPM) and electrochemical impedance spectroscopy (EIS) measurements were performed in order to analyze the charge transfer process of CPLE. Polarization curves indicate that CPLE acts through mixed mode inhibition. Impedance study reveals that the CPLE additives enhances the charge transfer resistance values and conversely decreases values of double layer capacitance. Scanning electron microscopy (SEM), Ultraviolet-Visible (UV-Vis) spectroscopy analysis and Fourier-Transform Infrared spectroscopy (FTIR) were done to confirm the Fe-CPLE complex formation on MS. The effect of temperature reveals that the inhibition efficiency increases with decrease in temperature and increase in concentration of CPLE (maximum of 4[Formula: see text]mg[Formula: see text]L[Formula: see text]). The adsorption of CPLE shows that it obeys Langmuir’s isotherm model with free energy of adsorption, [Formula: see text][Formula: see text]kJ mol[Formula: see text]. A suitable adsorption model is also proposed.


2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
T. K. Chaitra ◽  
K. N. Mohana ◽  
H. C. Tandon

Three new thiazole based pyridine derivatives 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-2-ylmethylene-hydrazide (2-MTPH), 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-3-ylmethylene-hydrazide (3-MTPH), and 5-(4-methoxy-phenyl)-thiazole-2-carboxylic acid pyridin-4-ylmethylene-hydrazide (4-MTPH) were synthesized and characterized. Corrosion inhibition performance of the prepared compounds on mild steel in 0.5 M HCl was studied using gravimetric, potentiodynamic polarisation, and electrochemical impedance techniques. Inhibition efficiency has direct relation with concentration and inverse relation with temperature. Thermodynamic parameters for dissolution and adsorption process were evaluated. Polarisation study reveals that compounds act as both anodic and cathodic inhibitors with emphasis on the former. Impedance study shows that decrease in charge transfer resistance is responsible for effective protection of steel surface by inhibitors. The film formed on the mild steel was investigated using FTIR, SEM, and EDX spectroscopy. Quantum chemical parameters likeEHOMO,ELUMO,ΔE, hardness, softness, and ionisation potential were calculated. Higher value ofEHOMOand lower value ofΔEindicate the better inhibition efficiency of the compounds. Lower ionisation potential of inhibitors indicates higher reactivity and lower chemical stability.


2018 ◽  
Vol 778 ◽  
pp. 111-117 ◽  
Author(s):  
Zaeem Ur Rehman ◽  
Mohsin Ali Raza ◽  
Faizan Ali Ghauri ◽  
Rumasa Kanwal ◽  
Akhlaq Ahmad ◽  
...  

In this study graphene coatings were deposited on mild steel substrate using feasible and environmental friendly method. The successful synthesis of graphite oxide was carried by the modified Hummer’s method. Graphene oxide (GO) coatings were developed from GO/water suspension using electrophoretic deposition (EPD). The EPD parameters voltage and deposition time were varied to deposit uniform adherent coatings. The coatings were post heat treated at 200 °C in vacuum for 4h to assess the effect on coated samples. GO and GO-EPD coating morphology were characterized using Fourier transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM) and Scanning electron microscopy (SEM). Linear polarization (LPR) and electrochemical impedance spectroscopy (EIS) tests were performed in saline solution to evaluate electrochemical response. Coatings were partially reduced due to removal of oxygen containing functional groups during EPD and post heat treatments. The GO post heat treated coating had better corrosion resistance ~2 times than that of bare mild steel and higher charge transfer resistance.


2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
A. K. Satpati ◽  
A. V. R. Reddy

Dissolution characteristics of copper in hydrochloric acid medium and the effect of 4-amino 1,2,4-triazole (ATA) on the corrosion process have been studied using conventional electrochemical techniques and rotating ring-disc electrodes (RRDEs). Corrosion potential () and corrosion current density () were obtained by Tafel extrapolation methods. Charge transfer resistance () and double-layer capacitance () were obtained from the electrochemical impedance spectroscopy (EIS). ATA was shown to be an effective inhibitor for the copper-corrosion inhibition in acid medium. The corrosion rate was retarded in presence of inhibitors mainly because of the adsorption of the inhibitor on the electrode surface. Adsorption of the inhibitor on the metal surface was found to follow the Langmuir adsorption isotherm. Standard free energy change of the adsorption process () was calculated to be −54.3 kJ mol−1; such a large negative value of suggests the prescence of a chemisorption process.


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