共查询到20条相似文献,搜索用时 31 毫秒
1.
R. A. Prabhu A. V. Shanbhag T. V. Venkatesha 《Journal of Applied Electrochemistry》2007,37(4):491-497
Tramadol[2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)cyclohexanol hydrate], a drug, was tested as a corrosion inhibitor for
mild steel in 0.5 M HCl and 0.25 M H2SO4 separately at 300, 310 and 320 K using mass loss and galvanostatic polarization techniques. The percentage protection efficiencies
were evaluated at different concentrations of the inhibitor at different temperatures. The protection efficiency increased
with increase in inhibitor concentration and decreased with increase in temperature in both the acid solutions. Galvanostatic
polarization studies showed that the inhibitor is of mixed type with a slight predominance of cathodic character. The inhibitor
was more active in HCl than in H2SO4. The maximum protection efficiency approached 82.6% in the presence of 2.16 × 10−3 M inhibitor. Some samples of mild steel were examined by scanning electron microscopy. The inhibitor was found to adsorb
on the mild steel surface according to the Langmuir adsorption isotherm. The thermodynamic functions of dissolution and adsorption
processes were evaluated. 相似文献
2.
S. Rengamani S. Muralidharan M. Anbu Kulandainathan S. Venkatakrishna Iyer 《Journal of Applied Electrochemistry》1994,24(4):355-360
The influence of aminophenols on the corrosion and hydrogen permeation of mild steel in 1 M HCl and 0.5 M H2SO4 has been studied using weight loss and gasometric measurements and various electrochemical techniques. All the isomers of aminophenol inhibit the corrosion of mild steel in 1 M HC1 and accelerate it in 0.5 M H2SO4. They behave predominantly as cathodic inhibitors. Aminophenols, except PAP in I M HCI, enhance the permeation current in both the acids. The adsorption of PAP on the mild steel surface in 1 M HCl obeys the Langmuir adsorption isotherm. Surface analysis and ultraviolet spectral studies are also carried out to establish the mechanism of corrosion inhibition and acceleration of mild steel in acidic solutions. 相似文献
3.
S. Muralidharan B. Ramesh Babu S. Venkatakrishna Iyer S. Rengamani 《Journal of Applied Electrochemistry》1996,26(3):291-296
The influence of aminobenzoic acids on the corrosion and hydrogen permeation through mild steel in 1 m HC1 and 0.5 M H2SO4 has been studied using weight loss and gasometric measurements and various electrochemical techniques. All the three isomers of aminobenzoic acid inhibit the corrosion of mild steel both in HC1 and H2SO4 in the order ortho > meta > para. It is observed that the inhibition is greater in HCI than in H2SO4. The predominant behaviour is in the cathodic inhibitor mode. These compounds reduce the permeation current in 111 HCl and enhance it in 0.51 v1 H2SO4. The adsorption of these compounds on mild steel in 1 m HC1 and 0.5 m H2SO4 obeys Langmuir's adsorption isotherm. 相似文献
4.
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
5.
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
6.
T. Sathiyapriya G. Rathika M. Dhandapani 《Journal of Adhesion Science and Technology》2013,27(22):2443-2461
The current research work was keen to examine the corrosion inhibition efficiency of mild steel (MS) in presence of aqueous extract of Araucaria heterophylla Gum (AHG) in 1?M H2SO4 medium. The phytoconstituents of the AHG were interpreted by GC-MS and corrosion inhibition efficiency was deduced using other techniques like weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Adsorption of inhibitor molecules on the mild steel surface was supported by Density Functional Theory (DFT) studies, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). It is seen from the results that the inhibitor exhibits optimum efficiency of 78.57% at 0.05% v/v on mild steel specimen in 1?M H2SO4 medium at room temperature. Tafel polarizations clearly show that the aqueous extract of AHG acts as a mixed type inhibitor. The change in the EIS parameters in presence of inhibitor is investigative of the protective layer formation of the mild steel surface. The adsorption is found to obey Langmuir adsorption isotherm. Thermodynamic and activation parameters for the corrosion inhibition process supported the physical adsorption mechanism. 相似文献
7.
Moses M. Solomon 《Journal of Adhesion Science and Technology》2013,27(11):1060-1080
The inhibition performance of poly (methacrylic acid) (PMAA) and the effect of addition of iodide ions on the inhibition efficiency for mild steel corrosion in 0.5 M H2SO4 solution were investigated in the temperature range of 303–333 K using electrochemical, weight loss, scanning electron microscopy (SEM), and water contact angles measurements. The results show that PMAA is a moderate inhibitor for mild steel in 0.5 M H2SO4 solution. Addition of small amount of KI to PMAA significantly upgraded the inhibition efficiency up to 96.7%. The adsorption properties of PMAA and PMAA + KI are estimated by considering thermodynamic and kinetic parameters. The results reveal that PMAA alone was physically adsorbed onto the mild steel surface, while comprehensive adsorption mode characterized the adsorption of PMAA + KI. Adsorption of PMAA and PMAA + KI followed Temkin adsorption isotherm. The SEM and water contact angle images confirmed the enhanced PMAA film formation on mild steel surface by iodide ions. 相似文献
8.
D. Thirumoolan Vikas A. Katkar G. Gunasekaran Tapan Kanai K. Anver Basha 《Progress in Organic Coatings》2014
Hyperbranched poly(cyanurateamine) (POCYAM) was tested as a novel corrosion inhibitor for mild steel in 0.5–3 M HCl using chemical and electrochemical techniques at 25–70 °C. The results show that this compound has good corrosion inhibiting properties for mild steel in HCl at very low concentrations. Corrosion inhibition efficiency rises with POCYAM concentration. The adsorption of the POCYAM onto the mild steel surface obeys Langmuir adsorption isotherm model. The inhibition mechanism was further corroborated by the values of thermodynamic parameters obtained from the experimental data. 相似文献
9.
Fouad Bentiss Mounim Lebrini Michel Traisnel Michel Lagrenée 《Journal of Applied Electrochemistry》2009,39(8):1399-1407
The synergistic effect of iodide ions on the corrosion inhibition of mild steel in 0.5 M H2SO4 solutions by 2,5-bis(4-methoxyphenyl)-1,3,4-thiadiazole (4-MTH) has been studied using electrochemical impedance spectroscopy
(EIS) and the Tafel polarisation method. The results showed that the inhibition efficiency increased with 4-MTH concentration
while the potential of desorption (E
d) remained unchanged. The addition of potassium iodide (KI) in the acid solution stabilized the adsorption of 4-MTH molecules
on the metal surfaces and, therefore, enhanced the inhibition efficiency of 4-MTH and increased the value of E
d. The synergistic effect was observed between KI and 4-MTH with an optimum mass ratio of [4-MTH]/[KI] = 5/5. The calculated
values of synergism parameter (S
θ) from the coverage of the surface were found to be more than unity in most cases. This clearly showed the synergistic influence
of iodide ions on the corrosion inhibition of mild steel in 0.5 M H2SO4 by 4-MTH. The adsorption of this inhibitor alone and in combination with iodide ions followed Langmuir’s adsorption isotherm. 相似文献
10.
The cationic surfactant cetylpyridinium chloride (CPC) showed high inhibition efficiency for the corrosion of low carbon steel in 1 M H2SO4. Electrochemical measurements were dedicated to test the performance of CPC at different concentrations and temperatures. CPC has a significant inhibiting effect on the corrosion of steel and protection efficiencies up to 97% were measured. The inhibitor shifted the corrosion potential in the cathodic direction. It was found that adsorption is consistent with the Bockris–Swinkels isotherm in the studied temperature range (30–60 °C). The negative values of the free energy of adsorption and the decrease in apparent activation energy in the presence of the inhibitor suggest chemisorption of the CPC molecule on the steel surface. 相似文献
11.
Mauro J. Banera José A. Caram Claudio A. Gervasi María V. Mirífico 《Journal of Applied Electrochemistry》2014,44(12):1337-1344
The inhibitory effect of 3a,6a-diphenyltetrahydro-1H-imidazo [4,5-c] [1, 2, 5] thiadiazole-5(3H)-thione 2,2-dioxide (TTU) on the corrosion behaviour of mild steel in 0.5 M H2SO4, at (30 ± 0.5) °C was studied by gravimetric, potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning electron microscopy measurements. The effect of inhibitor concentration on the corrosion rate, surface coverage and inhibition efficiency is investigated. Results show that TTU exerts a strong inhibiting effect on mild steel corrosion and acts as a cathodic-type inhibitor. TTU does not affect the mechanism of the cathodic reaction while the anodic reaction mechanism changes upon addition of the inhibitor. Possible mechanistic pathways for the inhibition process are proposed. The inhibition efficiency of TTU may be due to either the adsorption of inhibitor molecules building a protective film or the formation of an insoluble complex of the inhibitor with metal cations. TTU adsorption obeys the Langmuir model. 相似文献
12.
The influence of some fatty acid triazoles namely, 4-Phenyl-5-undecyl-4H- [1,2,4] triazole-3-thiol (PUTT), 5-Heptadec-8-enyl-4-phenyl-4H- [1,2,4] triazole-3-thiol (HPTT), and 5-Dec-9-enyl-4-phenyl-4H- [1,2,4] triazole-3-thiol (DPTT) on the corrosion of mild steel in 1 M hydrochloric acid (HCl) and 0.5 M sulfuric acid (H2SO4) was studied by weight loss and potentiodynamic polarization methods. The values of activation energy and free energy of adsorption of all the triazoles were calculated to investigate the mechanism of corrosion inhibition. The potentiodynamic polarization studies were carried out at room temperature, according to which all the compounds were mixed type inhibitors and inhibit the corrosion of mild steel by blocking the active sites of the metal. The adsorption of all the triazoles on mild steel surface in both the acid solutions was found to obey the Langmuir adsorption isotherm. All the compounds showed good inhibition efficiency in both acids. The inhibition efficiency of the compounds was found to vary with their nature and concentration, solution temperature and immersion time. Electrochemical impedance spectroscopy was also used to investigate the mechanism of the corrosion inhibition. 相似文献
13.
Three heterocyclic compounds namely 3-anilino-5-imino-4-phenyl-1, 2,4-thiadiazoline (AIPT), 3-anilino-5-imino-4-tolyl-1, 2,4-thiadiazoline (AITT), and 3-anilino-5-imino-4-chlorophenyl-1, 2,4-thiadiazoline (AICT) were synthesized and their influence on the inhibition of corrosion of mild steel in 1 M HCl and 0.5 M H2SO4 was investigated by weight loss and potentiodynamic polarization techniques. The values of activation energy and free energy of adsorption of these compounds were also calculated. Potentiodynamic polarization studies were carried out at room temperature, and showed that all the compounds were mixed type inhibitors causing blocking of active sites on the metal. The inhibition efficiency of the compounds was found to vary with concentration, temperature and immersion time. Good inhibition efficiency was evidenced in both acid solutions. The adsorption of the compounds on mild steel for both acids was found to obey the Langmuir adsorption isotherm. Electrochemical impedance spectroscopy was also used to investigate the mechanism of corrosion inhibition. 相似文献
14.
Corrosion inhibitory action of Commiphora caudata extract on the mild steel corrosion in 1 M H2SO4 acid medium is investigated by weight loss and electrochemical studies. The weight loss method shows that the inhibition efficiency increases with the increase of inhibitor concentration, time, and temperature. The polarization studies reveal that the extract acts as a mixed type inhibitor. In electrochemical impedance measurement, the semicircle curves indicated that the charge transfer process controlled the corrosion of mild steel. Thermodynamic parameter such as free energy value was negative, that indicates spontaneous adsorption of inhibitor on mild steel surface. In the presence of inhibitor decreases the activation energy value which shows the chemical adsorption. The Commiphora caudata extract is found to obey Langmuir adsorption isotherm. Scanning electron microscopy, FTIR, and Quantum chemical studies confirmed that the mild steel protect from the corrosion by adsorption of the inhibitor molecules on surface of metal. 相似文献
15.
Saviour A. Umoren 《Journal of Adhesion Science and Technology》2016,30(17):1858-1879
The toxic nature of most organic and inorganic corrosion inhibitors has necessitated the search for corrosion inhibitors with an excellent environmental profile. The present work is focused on the widening utilization of plant extracts for metallic corrosion control and reports on the corrosion inhibition effect of mustard seed extract (MSE) for typical X60 pipeline steel in 2 M HCl and 1 M H2SO4 solutions. Gravimetric and electrochemical (electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization) methods were employed. The effect of immersion time and temperature on the corrosion inhibition effect of the plant extract was also studied. Results obtained show that MSE inhibited the corrosion of steel in both media which was more pronounced in H2SO4 than in HCl environment. Inhibition efficiency increased with increase in the concentration of the extract but decreased with increase in temperature. The potentiodynamic polarization studies revealed that MSE functions as a mixed-type inhibitor. The corrosion inhibition is assumed to occur via adsorption of the components of the extract on the steel surface which was found to obey Langmuir adsorption isotherm model. The morphology of the corroding steel surface in the absence and presence of the MSE was visualized using scanning electron microscopy. 相似文献
16.
Inhibitive and adsorption properties of ethanol extract of Lasianthera africana for inhibition of corrosion of mild steel in H2SO4 were studied using gravimetric, thermometric, gasometric, and infrared (IR) methods. The extract was found to be a good inhibitor
of corrosion of mild steel in H2SO4. Inhibitive properties of the extract were attributed to enhancement in adsorption of the inhibitor on mild-steel surface
by saponin, alkaloid, tannin, flavanoid, cardiac glycoside, and anthraquinone (present in the extract). Also, adsorption of
the inhibitor was found to be exothermic, spontaneous, and consistent with assumptions of Langmuir and Temkin adsorption isotherms.
Synergistic study revealed that, of the investigated halides, only KCl may enhance adsorption of the inhibitor, whereas KBr
and KI antagonized its adsorption. Based on the decrease in efficiency of the inhibitor with temperature, with values of activation
energy and free energy of adsorption below the threshold values of −40 and 80 kJ mol−1, respectively, a physical adsorption mechanism has been proposed for adsorption of ethanol extract of Lasianthera africana on the surface of mild steel. 相似文献
17.
S. Syed Azim S. Muralidharan S. Venkatakrishna Iyer 《Journal of Applied Electrochemistry》1995,25(5):495-500
The synergistic action caused by iodide ions on the corrosion inhibition of mild steel in 0.5 M H2S04 in the presence of dicyclohexylamine (DCHA) has been investigated using potentiodynamic polarization, linear polarization and a.c. impedance techniques. DCHA inhibits the corrosion of mild steel in 0.5 m H2SO4 even at lower concentrations. The inhibition efficiency decreases with increase in the concentration of the amine. The addition of iodide ions enhances the inhibition efficiency to a considerable extent. The adsorption of this compound is also found to obey Langmuir's adsorption isotherm, thereby indicating that the main process of inhibition is by adsorption. The increase in surface coverage values in the presence of iodide ions indicates that DCHA forms an insoluble complex at lower amine concentrations by undergoing a joint adsorption. The synergism parameter (S) is defined and calculated both from inhibition efficiency and surface coverage values. This parameter in the case of DCHA is found to be more than unity, indicating that the enhanced inhibition efficiency caused by the addition of iodide ions is only due to synergism and there is a definite contribution from the inhibitor molecule. Thus, DCHA is then adsorbed by coulombic attraction on the metal surface where the I– is already chemisorbed and thus reduces the corrosion rate. 相似文献
18.
Effect of iodide ions on corrosion inhibition of mild steel by 3,5-bis(4-methylthiophenyl)-4H-1,2,4-triazole in sulfuric acid solution 总被引:2,自引:0,他引:2
F. Bentiss M. Bouanis B. Mernari M. Traisnel M. Lagrenee 《Journal of Applied Electrochemistry》2002,32(6):671-678
The synergistic effect of iodide ions on the corrosion inhibition of mild steel in 0.5 M sulfuric acid (H2SO4) in the presence of 3,5-bis(4-methylthiophenyl)-4H-1,2,4-triazole (4-MTHT) was investigated using weight loss measurements and different electrochemical techniques such as potentiostatic polarization curves and electrochemical impedance spectroscopy (EIS). The inhibition efficiency (E, %) increased with 4-MTHT concentration, but the desorption potential (E
d) remained unchanged with increasing 4-MTHT concentration. The addition of potassium iodide (KI) enhanced E considerably and increased the value of E
d. A synergistic effect was observed between KI and 4-MTHT with an optimum mass ratio of [4-MTHT]/[KI] = 4 × 10–2. The synergism parameters (S
) calculated from surface coverage were found to be more than unity. This result clearly showed the synergistic influence of iodide ions on the corrosion inhibition of mild steel in 0.5 M H2SO4 by 4-MTHT. The adsorption of this inhibitor alone and in combination with iodide ions followed Langmuir's adsorption isotherm. 相似文献
19.
The corrosion inhibitive effects of Pachylobus edulis exudate gum for mild steel in 2 M H2SO4 and influence of potassium halide additives on the inhibition efficiency were investigated using hydrogen evolution and thermometric methods at 30°–60°C. Inhibition efficiency was determined by comparing the corrosion rates in the absence and presence of additives. The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition. It was found that the exudate gum acts as an inhibitor for acid-induced corrosion of mild steel. Inhibition efficiency (%I) of the exudate gum increased with an increase in concentration of the exudate gum and synergistically increased on addition of potassium halides but decreased with increase in temperature. Inhibitor adsorption characteristics were approximated by Temkin adsorption isotherm at all the concentrations and temperatures studied. The phenomenon of physical adsorption is proposed from the activation parameters obtained. 相似文献
20.
The inhibitive effect of hydroxyethyl cellulose (HEC) on mild steel corrosion in aerated 0.5 M H2SO4 solution was studied using gravimetric and electrochemical techniques. The effect of temperature on corrosion and inhibition was also investigated. The results show that hydroxyethyl cellulose functioned as a good inhibitor in the studied environment and inhibition efficiency increased with concentration of inhibitor. Potentiodynamic polarization measurements revealed that HEC inhibited both the cathodic and anodic partial reactions of the corrosion processes. Impedance results clearly show that HEC inhibited the corrosion reaction by adsorption onto the metal/solution interface by significantly decreasing the double layer capacitance (C dl ). This result was greatly pronounced in the presence of the inhibitor system (HEC + KI) that contains halide additive. Temperature studies revealed an increase in inhibition efficiency with rise in temperature. The adsorption behavior was found to obey the Freundlich isotherm. The values of activation energy, heat of adsorption, and standard free energy suggest that there was transition from physical to chemical adsorption mechanism of HEC on the mild steel surface. Quantum chemical calculations using the density functional theory (DFT) was employed to determine the relationship between molecular structure and inhibition efficiency. 相似文献