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1.
The inhibition effect of 2-mercaptothiazoline (2MT) on the corrosion behavior of mild steel (MS) in 0.5 M HCl solution was studied in both short and long immersion times (120 h) using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques. For long-term tests, hydrogen gas evolution (VH2−t) and the change of the open circuit potential with immersion time (Eocp − t) were also measured in addition to the former three techniques. The surface morphology of the MS after its exposure to 0.5 M HCl solution with and without 1.0 × 10−2 M 2MT with the different immersion times was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal stability of the inhibitor film was investigated by thermogravimetric analysis (TGA). The value of activation energy (Ea) for the MS corrosion and the thermodynamic parameters such as adsorption equilibrium constant (Kads), free energy of adsorption (ΔGads), adsorption heat (ΔHads) and adsorption entropy (ΔSads) values were calculated and discussed. The potential of zero charge (PZC) of the MS in inhibited solution was studied by the EIS method, and a mechanism for the adsorption process was proposed. The results showed that 2MT performed excellent inhibiting effect for the corrosion of the MS. Finally, the high inhibition efficiency was discussed in terms of adsorption of inhibitor molecules and protective film formation on the metal surface. TGA results also indicated that the inhibitor film on the surface had a relatively good thermal stability. 相似文献
2.
Corrosion inhibition property of N-(phenylcarbamothioyl)benzamide (PCB) on mild steel in 1.0 M HCl solution has been investigated using chemical (weight loss method) and electrochemical techniques (potentiodynamic polarization and AC impedance spectroscopy). The inhibition efficiencies obtained from all the methods are in good agreement. The thiourea derivative is found to inhibit both anodic and cathodic corrosion as evaluated by electrochemical studies. The inhibitor is adsorbed on the mild steel surface according to Langmuir adsorption isotherm. The adsorption mechanism of inhibition was supported by spectroscopic (UV-visible, FT-IR, XPS), and surface analysis (SEM-EDS) and adsorption isotherms. The thermodynamic parameter values of free energy of adsorption (ΔGads) reveals that inhibitor was adsorbed on the mild steel surface via both physisorption and chemisorption mechanism. 相似文献
3.
《Journal of Industrial and Engineering Chemistry》2014,20(5):2819-2829
Inhibition effect of three bis-Schiff bases of isatin namely (2-methoxybenzylidene) hydrazono) indolin-2-one (HZ-1), (2-hydroxybenzylidene) hydrazono) indolin-2-one (HZ-2) and (4-nitrobenzylidene) hydrazono) indolin-2-one (HZ-3) was studied on mild steel corrosion in 1.0 M HCl by gravimetric measurements, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and quantum chemical study. The values of activation energy (Ea), equilibrium constant (Kads), free energy of adsorption ΔG°ads, activation enthalpy ΔH* and activation entropy ΔS*were discussed. The adsorption of inhibitors on metal followed Langmuir's adsorption isotherm. SEM and EDX observations confirmed the existence of protective inhibitor film on metal surface. Quantum chemical study supports the comparative inhibition effect of HZs. 相似文献
4.
Qi Bo Zhang Yi Xin Hua Tie Guang Dong Dan Gui Zhou 《Journal of Applied Electrochemistry》2009,39(8):1207-1216
The effects of temperature and current density on cathodic current efficiency, specific energy consumption, and zinc deposit
morphology during zinc electrodeposition from sulfate electrolyte in the presence of 1-butyl-3-methylimidazolium hydrogen
sulfate ([BMIM]HSO4) as additive were investigated. The highest current efficiency (93.7%) and lowest specific energy consumption (2,486 kWh t−1) were achieved at 400 A m−2 and 313 K with addition of 5 mg dm−3 [BMIM]HSO4. In addition, the temperature dependence of some kinetic parameters for the zinc electrodeposition reaction was experimentally
determined. Potentiodynamic polarization sweeps were carried out to obtain the expression for each parameter as a function
of temperature. In the condition studied, the exchange current density depended on temperature as ln(i
0) = −a/T + b and the charge transfer coefficient was constant. Moreover, the adsorption of the additive on cathodic surface obeyed the
Langmuir adsorption isotherm. The associated thermodynamic parameters indicated the adsorption to be chemical. 相似文献
5.
Photo-cross-linkable polymers namely, poly((E)-(1-(5-(4-(3-(4-chlorophenyl)-3-oxoprop-1-enyl)phenoxy)pentyl)-1H-1,2,3-triazol-4-yl)methyl acrylate) (Cl-5) and poly((E)-(1-(5-(4-(3-(4-chlorophenyl)-3-oxoprop-1-enyl)phenoxy)decyl)-1H-1,2,3-triazol-4-yl)methyl acrylate) (Cl-10) were synthesized by click-chemistry. The polymers were characterized by using various spectroscopic techniques and the rate of cross-linking was evaluated by absorption spectroscopy. The inhibitory action of the photo-cross-linkable polymers was evaluated for mild steel (MS) corrosion in 1.0 M hydrochloric acid solution (HCl) by means of electrochemical impedance spectroscopy, potentiodynamic polarization measurements, adsorption isotherms and surface analysis. To the best of our knowledge, these are the most efficient inhibitors (Cl-5 and C-10) for the corrosion of MS in HCl reported so far. Tafel polarization measurements showed that the polymers act as mixed type inhibitors and the adsorption of the inhibitors onto the MS surface followed the Langmuir adsorption isotherm. The values of the Gibbs free energy of adsorption (ΔGads) strongly supported spontaneous physicochemical adsorption of inhibitor molecules on the MS surface. The SEM-EDX results confirmed that the cross-linked polymers inhibited the corrosion to a greater extent than the intact polymer. 相似文献
6.
The effect of antimony(III) on the cathodic current efficiency (CE), power consumption (PC), deposit morphology, and polarization
behavior during electrodeposition of zinc from acidic sulfate solutions containing 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO4 was investigated. The results indicated that the addition of Sb(III) alone decreased the CE, increased the PC, and deteriorated
the quality of the zinc electrodeposits. However, the combined addition of Sb(III) and [BMIM]HSO4 was found to be beneficial for zinc deposition and improved the surface morphology of the zinc electrodeposits. Maximum CE
and minimum PC were obtained at the combined addition of 0.02 mg dm−3 Sb(III) and 5 mg dm−3 [BMIM]HSO4. Depolarization of the cathode was noted in the presence of Sb(III) alone in the electrolyte whereas this effect was partly
counteracted by the addition of [BMIM]HSO4. Cathodic polarization curves were traced and analyzed to determine the electrokinetic parameters such as Tafel slope, transfer
coefficient, and exchange current density so as to elucidate the nature of the electrode reactions. The data obtained from
X-ray diffractogram revealed that the presence of Sb(III) did not change the structure of the electrodeposited zinc but affected
the crystallographic orientation of the crystal planes. 相似文献
7.
The nucleation and first stages of the growth of zinc on aluminum from acidic sulfate solution in the absence and presence
of 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO4 as additive were investigated using cyclic voltammetry, chronoamperometric current–time transients, and scanning electron
microscopy techniques. The dimensionless chronoamperometric current–time transients for the zinc electrodeposition on aluminum
electrode from the solution free of [BMIM]HSO4 showed the zinc deposition can be interpreted by a model involving instantaneous nucleation with hemispherical diffusion
controlled growth of nuclei. The addition of [BMIM]HSO4 induced a blocking effect on the zinc electrocrystallization process through its cathodic adsorption on the electrode surface.
This effect led to increase the number density of active sites, decrease the nucleation and growth rate of these nuclei, and
produce more leveled and fine-grained cathodic deposits without affecting the instantaneous nucleation mechanism. Surface
morphology analysis revealed the crystal structure of the zinc deposits formed did not change by the adsorption of [BMIM]HSO4 at the first stages of deposition. 相似文献
8.
Kumaravel Mallaiya Rameshkumar Subramaniam Subramanian Sathyamangalam Srikandan S. Gowri N. Rajasekaran A. Selvaraj 《Electrochimica acta》2011,(11):3857
The corrosion inhibition efficiency of a newly synthesized Schiff's base for the corrosion of mild steel was studied in 1.0 M HCl and 0.5 M H2SO4 solutions. The results of weight loss measurements, electrochemical impedance and potentiodynamic polarization measurements consistently demonstrated that the Schiff's base synthesized is a good corrosion inhibitor with an inhibitory efficiency of approximately 92% at an optimum inhibitor concentration of 600 mg/L. The inhibition in both of the corrosive media was observed to be a mixed type. The potential of zero charge (PZC) at the metal–solution interface was determined for both the inhibited and uninhibited solutions to provide the mechanism of inhibition. The inhibitor formed a film on the metal surface through chloride or sulfate bridges depending upon the medium. The temperature dependence of the corrosion rate was also studied in the temperature range from 27 to 50 °C. The value of the activation energy (Ea) calculated showed that the inhibition film formation on the metal surface occurred through chemisorption. The thermodynamic parameters such as the adsorption equilibrium constant (Kads) and the free energy of adsorption (ΔGads) were calculated and discussed. Several adsorption isotherms were tested and the experimental data fit well with the Langmuir adsorption isotherm. 相似文献
9.
10.
Daisuke Kodama Mitsuhiro Kanakubo Masaki Kokubo Hajime Kawanami Hiroshi Nanjo 《The Journal of Supercritical Fluids》2010,52(2):189-192
The solubilities of CO2 and the liquid densities in a Brønsted acid-base ionic liquid, [DMFH][Tf2N], composed of N,N-dimethylformamide (DMF) and bis(trifluoromethanesulfonyl)amide (HTf2N) have been investigated at high pressures and at different temperatures. The results were compared with those in DMF and a typical 1-butyl-3-methylimidazolium analogue with the same anion, [BMIM][Tf2N]. The mole fraction scaled solubilities of CO2 in the three liquids showed a slight increase in the following order, DMF < [DMFH][Tf2N] < [BMIM][Tf2N], whereas more remarkable difference was observed in the volume scaled concentrations of CO2, [BMIM][Tf2N] < [DMFH][Tf2N] « DMF, mainly due to the bulkiness of liquid entities. 相似文献
11.
Devarayan Kesavan Manoharan Muthu Tamizh Mayakrishnan Gopiraman Nagarajan Sulochana Ramasamy Karvembu 《Journal of surfactants and detergents》2012,15(5):567-576
A series of 4-substituted N-(2-mercaptophenyl)salicylideneimine Schiff bases were synthesized and investigated for corrosion inhibition of mild steel in hydrochloric acid medium. Inhibition through adsorption mechanism is proposed for these inhibitors, which is well supported by electrochemical impedance spectroscopy, the Langmuir adsorption isotherm and Scanning Electron Microscope morphologies of inhibited and uninhibited mild steel specimens. The negative ?G ads indicates the spontaneous adsorption of the inhibitor on a mild steel surface. Among all the examined inhibitors, 5-bromo-N-(2-mercaptophenyl)salicylideneimine showed a higher inhibition efficiency. In order to reveal the usefulness of these Schiff bases as corrosion inhibitors under various circumstances, weight loss measurements were performed at various temperatures, acid concentrations and immersion times. 相似文献
12.
The adsorption and inhibition effect of vanillin (4-hydroxy-3-methoxy-benzaldehyde) on cold rolled steel (CRS) in 3.0 M H3PO4 at 30–60 °C was investigated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The results show that inhibition efficiency increases with the inhibitor concentration, while decreases with temperature. The adsorption of vanillin obeys Temkin adsorption isotherm. The thermodynamic parameters (adsorption enthalpy ΔHads, adsorption free energy ΔGads and adsorption entropy ΔSads) have been calculated and discussed in detail. Polarization curves show that vanillin acts as a mixed-type inhibitor. EIS shows that charge transfer resistance increases while the capacitance of double layer decreases with the inhibitor concentration, confirming the adsorption process mechanism. The adsorbed film on CRS surface containing vanillin was examined by atomic force microscope (AFM). Quantum chemical calculation was applied to elucidate the adsorption mode of the inhibitor molecule onto steel surface. Depending on the results, the inhibitive mechanism is proposed from the viewpoint of adsorption theory. 相似文献
13.
R. Fuchs-Godec 《Electrochimica acta》2007,52(15):4974-4981
The corrosion inhibition characteristics of non-ionic surfactants of the TRITON-X series, known as TRITON-X-100 and TRITON-X-405, on stainless steel (SS) type X4Cr13 in sulphuric acid were investigated by potentiodynamic polarisation measurements. It was found that these surfactants act as good inhibitors of the corrosion of stainless steel in 2 mol L−1 H2SO4 solution, but the inhibition efficiency strongly depends on the electrode potential. The polarisation data showed that the non-ionic surfactants used in this study acted as mixed-type inhibitors and adsorb on the stainless steel surface, in agreement with the Flory-Huggins adsorption isotherm. Calculated ΔGads values are −57.79 kJ mol−1 for TRITON-X-100, and −87.5 kJ mol−1 for TRITON-X-405. From the molecular structure it can be supposed that these surfactants adsorb on the metal surface through two lone pairs of electrons on the oxygen atoms of the hydrophilic head group, suggesting a chemisorption mechanism. 相似文献
14.
Pitchai Sakunthala Shanmuga Sundaram Vivekananthan Mayakrishnan Gopiraman Nagarajan Sulochana Alex Ramani Vincent 《Journal of surfactants and detergents》2013,16(2):251-263
The influences of Polycarpaea corymbosa (PC) and Desmodium triflorum (DT) leaf extracts on the corrosion behavior of mild steel (MS) in 1.0 M HCl was investigated by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The effect of temperature on the corrosion behavior of MS in 1.0 M HCl with the addition of plant extracts was studied in the temperature range of 300 K–320 ± 1 K. The results revealed that PC and DT were excellent green inhibitors and the inhibition efficiencies obtained from weight loss and electrochemical experiments were in good agreement. Inhibition efficiencies up to 91.78 % for PC and 92.99 % for DT were obtained. Potentiodynamic polarization studies revealed that both the inhibitors behaved as mixed‐type inhibitors. Adsorption behavior of these green inhibitors on the MS surface was found to obey the Langmuir adsorption isotherm. The thermodynamic parameter values of free energy of adsorption (?Gads) and enthalpy of adsorption (?Hads) revealed that each inhibitor was adsorbed on the MS surface via both chemisorption and physisorption mechanisms. The adsorption mechanism of inhibition was supported by FT–IR, UV–Visible, WAXD and SEM–EDS. 相似文献
15.
The corrosion behaviour of mild steel in 0.5 M H2SO4 solution containing various concentrations of a p-toluene sulphonic acid doped copolymer formed between aniline and o-toluidine was investigated using weight loss, polarization and electrochemical impedance techniques. The copolymer acted
as an effective corrosion inhibitor for mild steel in sulphuric acid medium. The inhibition efficiency has been found to increase
with increase in inhibitor concentration, solution temperature and immersion time. Various parameters like E
a for corrosion of mild steel in presence of different concentrations of inhibitor and ΔG
ads, ΔH
0, ΔS
0 for adsorption of the inhibitor, revealed a strong interaction between inhibitor and mild steel surface. The adsorption of
this inhibitor on the mild steel surface obeyed the Langmuir adsorption equation. 相似文献
16.
Velayutham Rajeswari Devarayan Kesavan Mayakrishnan Gopiraman Periasamy Viswanathamurthi 《Journal of surfactants and detergents》2013,16(4):571-580
Three Schiff bases, 2-acetylpyridine thiosemicarbazone (I 1 ), 2-acetylpyridine-(4-methylthiosemicarbazone) (I 2 ), and 2-acetylpyridine-(4-phenylthiosemicarbazone) (I 3 ) were tested against corrosion of cast iron in aqueous solutions of HCl, NaOH, NH4Cl, and NaCl by means of a mass loss method and electrochemical measurements. The inhibition efficiency is directly proportional to inhibitor concentration, while it decreases with prolonged immersion time and at low temperatures. In order to study the effect of an additive, synergism of KI was also studied. The adsorption of Schiff bases in corrosive media obeys Langmuir’s isotherm, both in the presence and absence of KI. The UV–Vis, FT-IR, WAXD and SEM analyses were carried out to support the mechanism of corrosion inhibition. The ΔG ads values reveal that the inhibition was mainly due to physisorption of the inhibitor molecules on the surface of cast iron. The electrochemical polarization results showed the predominantly cathodic nature of the inhibitors. 相似文献
17.
A comparative study of the effect of 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO4 and gelatine on current efficiency (CE), power consumption (PC), deposit morphology, and polarization behaviour of the cathode
during electrodeposition of zinc from acidic sulphate solutions were investigated. Compared with the traditional industrial
additive, gelatine, the addition of [BMIM]HSO4 was found to increase current efficiency, reduce power consumption, and improve the surface morphology. Maximum CE and minimum
PC were obtained at the addition dosage of 5 mg dm−3. Meanwhile, simultaneous addition of the two additives induced a blocking effect of the zinc reduction and led to more leveled
and fine-grained cathodic deposits. Moreover, cyclic voltammetry results and kinetic parameters such as Tafel slope, transfer
coefficient, and exchange current density obtained from Tafel plots led to the conclusion that both additives have a pronounced
inhibiting effect on Zn2+ electroreduction. The data obtained from X-ray diffractogram revealed that the presence of additives did not change the structure
of the electrodeposited zinc but affected the crystallographic orientation of the crystal planes. 相似文献
18.
Three new Schiff bases, viz., N,N′-ethylen-bis (salicylidenimine) [S1], N,N′-isopropylien-bis (salicylidenimine) [S2], and N-acetylacetone imine, N′-(2-hydroxybenzophenone imine) ortho-phenylen [S3] have been investigated as corrosion inhibitors for mild steel in 0.5 M H2SO4 using Tafel polarization and electrochemical impedance spectroscopy (EIS). The three Schiff bases function as good inhibitors reaching inhibition efficiencies of ∼97-98% at 300 ppm concentration. The fraction <theta> of the metal surface covered by the inhibitor is found to increase with inhibitor concentration. Of the three Schiff bases, the S2 shows better efficiency than the other two Schiff bases. The adsorption of the inhibitor follows Langmuir isortherm. Thermodynamic calculations indicate the adsorption to be physical in nature. 相似文献
19.
Mohamed Samir S Morad Abo El‐Hagag A Hermas Mohamed S Abdel Aal 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(4):486-494
Research on non‐toxic inhibitors is of considerable interest in investigations into the replacement of hazardous classical molecules. This paper reports the action of four amino acids containing sulfur on the corrosion of mild steel in phosphoric acid solution with and without Cl?, F? and Fe3+ ions near and at the corrosion potential (Ecorr) using both the polarization resistance method and electrochemical impedance spectroscopy (EIS). Both cysteine and N‐acetylcysteine (ACC) showed higher inhibition efficiency than methionine and cystine. Adsorption of methionine onto a mild steel surface obeys the Frumkin adsorption isotherm and has a free energy of adsorption value (ΔG °ads) lower than those obtained in the presence of cystine, cysteine and ACC whose adsorption isotherms follow that of Langmuir. Both F? and Fe3+ ions stimulate mild steel corrosion while Cl? ions inhibit it. The binary mixtures of methionine, cysteine or ACC with Cl? or F? ions are effective inhibitors (synergism) while the combinations of the amino acid with Fe3+ or the ternary Cl?/F?/Fe3+ mixture have low inhibitive action (antagonism). EIS measurements revealed that the charge transfer process mainly controls the mechanism of mild steel corrosion in phosphoric acid solution in the absence and presence of the investigated additives. The mechanism of corrosion inhibition or acceleration is discussed. © 2002 Society of Chemical Industry 相似文献
20.
The inhibition action of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) ionic liquids towards carbon steel corrosion in alkaline chloride solution was investigated by electrochemical measurements. The morphology of the surface was examined by atomic force microscopy (AFM), and the surface composition was evaluated via X-ray photoelectron spectroscopy (XPS) as well in order to verify the presence of inhibitor on the carbon steel surface. The results showed that the compound effectively suppressed both cathodic and anodic processes of carbon steel corrosion in alkaline solution by multi-center adsorption on carbon steel surface according to Langmuir adsorption isotherm, and acted as a mixed type inhibitor. The inhibition mechanism was proposed based on the viewpoint of complex physic-chemical interactions between the cationic inhibitor molecule and the carbon steel surface. 相似文献