共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
The inhibition effect of methyl violet (MV) on the corrosion of cold rolled steel (CRS) in 1.0 M sulfuric acid (H2SO4) was investigated by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods.
The results show that MV is a good inhibitor, and inhibition efficiency increases with inhibitor concentration, while decreases
with the temperature. The adsorption of MV on CRS surface obeys Langmuir adsorption isotherm equation. The thermodynamic parameters
of adsorption enthalpy (ΔH°), adsorption free energy (ΔG°) and adsorption entropy (ΔS°) are calculated and discussed. Potentiodynamic polarization curves show that MV acts as a mixed-type inhibitor in sulfuric
acid. EIS exhibits one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process.
Inhibition efficiency values obtained from weight loss, polarization and EIS are in reasonably good agreement. The adsorbed
film on CRS surface containing optimum dose of MV was investigated by Fourier transform infrared spectroscopy (FTIR) and scanning
electron microscopy (SEM). Depending on the results, the inhibitive mechanism is proposed from the viewpoint of adsorption
theory. 相似文献
3.
H. Ashassi-Sorkhabi B. Masoumi P. Ejbari E. Asghari 《Journal of Applied Electrochemistry》2009,39(9):1497-1501
The inhibition performance of Basic yellow 13 dye on mild-steel corrosion in hydrochloric acid solution was studied at 25 °C
using weight loss and electrochemical techniques. The effect of inhibitor concentration on inhibition efficiency has been
studied. Inhibition efficiency increased with increase of Basic yellow 13 concentration. The results showed that this inhibitor
had good corrosion inhibition even at low concentrations (95% for 0.005 M Basic yellow 13) and its adsorption on mild-steel
surface obeys Langmuir isotherm. ΔG
ads was calculated and its negative value indicated spontaneous adsorption of the Basic yellow 13 molecules on the mild-steel
surface and strong interaction between inhibitor molecules and metal surface. The value of ΔG
ads was less than 40 kJmol−1, indicating electrostatic interaction between the charged inhibitor molecules and the charged metal surface, i.e., physical
adsorption. 相似文献
4.
Xiang-Hong Li Shu-Duan Deng Hui Fu Guan-Nan Mu 《Journal of Applied Electrochemistry》2009,39(7):1125-1135
The inhibition effect of tween-85 on the corrosion of cold rolled steel (CRS) in 1.0 M hydrochloric acid (HCl) was studied
by weight loss and potentiodynamic polarization methods. The results show that tween-85 is a good inhibitor in 1.0 M HCl and
its maximum inhibition efficiency (IE) is 92% at very low concentration. Its adsorption obeys the Langmuir adsorption isotherm
equation. The thermodynamic parameters of adsorption enthalpy (ΔH
0), adsorption free energy (ΔG
0) and adsorption entropy (ΔS
0) were calculated and discussed. Polarization curves show that tween-85 acts as a mixed-type inhibitor in hydrochloric acid.
IE values obtained from weight loss and polarization are consistent. The adsorbed film on a CRS surface containing an optimum
dose of tween-85 was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS)
and atomic force microscope (AFM). An inhibitive mechanism is proposed from the viewpoint of adsorption theory. 相似文献
5.
The adsorption and inhibitive action of hexadecylpyridinium bromide (HDPB) on the corrosion of cold rolled steel (CRS) in
phosphoric acid produced by dihydrate wet method process (7.0 M H3PO4) was studied by weight loss, open circuit potential (OCP), potentiodynamic polarization curves, electrochemical impedance
spectroscopy (EIS), scanning electron microscope (SEM), and atomic force microscopy (AFM) methods. The results show that HDPB
is a good inhibitor in 7.0 M H3PO4, and its maximum inhibition efficiency (IE) is higher than 90% at little concentrations. The adsorption of HDPB obeys Langmuir
adsorption isotherm equation. Thermodynamic parameters (adsorption enthalpy ∆H
0, adsorption free energy ∆G
0, and adsorption entropy ∆S
0) were calculated and discussed. Polarization curves show that HDPB acts as a mixed-type inhibitor in phosphoric acid. EIS
shows that charge-transfer resistance increases with the inhibitor concentration, confirming adsorption process mechanism.
The inhibition action of HDPB could also be evidenced by SEM and AFM images. A probable inhibitive mechanism is proposed from
the viewpoint of adsorption theory. 相似文献
6.
Thiourea derivatives namely, phenylthiourea (PTU), N, N′-diphenylthiourea (DPTU) and N-naphtyl N′-phenylthiourea (NPTU) synthesised in our laboratory, were tested as inhibitors for the corrosion of cold rolled steel in
1 M HClO4 using polarisation and electrochemical impedance measurements. At 30 °C, PTU and DPTU stimulated corrosion at low concentrations
while addition of NPTU caused inhibition at all concentrations. The best protection (93%) was obtained by adding NPTU at 2.5 × 10−4 M. Polarisation curves showed that NPTU acted as a mixed inhibitor. The degree of surface coverage of the adsorbed inhibitors
was determined by the ac impedance technique. The adsorption of NPTU on the cold rolled steel surface obeyed the Langmuir
adsorption isotherm. Corrosion behaviour in the presence of NPTU at various concentrations was studied in the temperature
range 20–50 °C. Both the corrosion rate of cold rolled steel and protection efficiency increased with increasing temperature.
Activation energies with and without NPTU were obtained from the temperature dependence of corrosion current. The thermodynamic
functions of the adsorption processes were calculated from the polarisation data and were used to analyse the inhibitor adsorption
mechanism. 相似文献
7.
Role of some thiadiazole derivatives as inhibitors for the corrosion of C-steel in 1 M H<Subscript>2</Subscript>SO<Subscript>4</Subscript> 总被引:1,自引:0,他引:1
Inhibition of C-steel corrosion by some thiadiazole derivatives (I–VI) in 1 M H2SO4 was investigated by weight loss, potentiodynamic polarization, linear polarization resistance (LPR) and electrochemical impedance
spectroscopy (EIS) techniques. The presence of these compounds in the solution decreases the double layer capacitance, increases
the charge transfer resistance and increase of linear polarization. Polarization studies were carried out at room temperature,
and showed that all the compounds studied are mixed type inhibitors with a slight predominance of cathodic character. The
effect of temperature on corrosion inhibition has been studied and the thermodynamic activation and adsorption parameters
were calculated and discussed. Electrochemical impedance was used to investigate the mechanism of corrosion inhibition. The
adsorption of the compounds on C-steel was found to obey Langmuir’s adsorption isotherm. The synergistic effect brought about
by combination of the inhibitors and KSCN, KI and KBr was examined and explained. The mechanism of inhibition process was
discussed in the light of the chemical structure and quantum-chemical calculations of the investigated inhibitors. 相似文献
8.
M. Gopiraman P. Sakunthala D. Kesavan V. Alexramani I. S. Kim N. Sulochana 《Journal of Coatings Technology and Research》2012,9(1):15-26
Inhibition effect of Brugmansia suaveolens (BS) and Cassia roxburghii (CR) on mild carbon steel in 1.0 M HCl solution was studied. Inhibition efficiency of plant extracts were carried out by
using chemical (weight loss method) and electrochemical techniques (potentiodynamic polarization and electrochemical impedance
spectroscopy). The effect of temperature on the corrosion behavior of mild carbon steel in 1.0 M HCl with addition of plant
extracts was studied in the temperature range of 300–320 ± 1 K. Inhibition efficiencies up to 94.69 for BS and 93.22 for CR
can be obtained. The adsorption mechanism of inhibition was supported by FT-IR, surface analysis (SEM–EDS), and adsorption
isotherms. The thermodynamic parameter values of free energy of adsorption (∆G
ads) reveal that inhibitor was adsorbed on the mild carbon steel surface via both physisorption and chemisorption mechanisms. 相似文献
9.
Zhen-Yu Wu Zheng Fang Ling-Guang Qiu Yun Wu Zong-Qun Li Tao Xu Wei Wang Xia Jiang 《Journal of Applied Electrochemistry》2009,39(6):779-784
The inhibitive synergistic effect between a cationic gemini surfactant, 1,3-propane-bis(dimethyl dodecylammonium bromide)
(12-3-12), and bromide ion for the corrosion inhibition of cold rolled steel in 0.5 mol L−1 H2SO4 was investigated by weight loss, potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS). The
inhibition system composed by 12-3-12 and bromide ion is efficient. The adsorption mechanism of the 12-3-12 and bromide ion
on steel in acidic medium is discussed on the basis of experimental data and an adsorption model is proposed. Adsorption of
inhibitor system on the mild steel surface in acidic medium obeys Langmuir’s adsorption isotherm. In addition, potentiodynamic
polarization studies show that the system acts as a mixed-type inhibitor. Electrochemical impedance spectroscopy also suggests
the formation of a protective layer on the steel surface by the adsorption of surfactant molecules and bromide ions. 相似文献
10.
M. S. Morad 《Journal of Applied Electrochemistry》2008,38(11):1509-1518
Rp, potentiodynamic polarization curves and EIS techniques were applied to study the effect of five S-containing amino acids
on the corrosion of mild steel in 5% sulfamic acid solution at 40 °C. The compounds are effective inhibitors and the inhibition
efficiency follow the order: N-acetylcysteine (ACC) > cysteine (RSH) > S-benzylcysteine (BzC) > cystine (RSSR) ≅ methionine (CH3SR). The inhibitors affect the anodic dissolution of steel by blocking the anodic sites of the surface. EIS measurements indicated
that charge transfer is the rate determining step in the absence and presence of the inhibitors and the steel/solution interface
can be represented by the equivalent circuit Rs(RctQdl). Adsorption of RSH, CH3SR and RSSR follows the Langmuir model while the Temkin isotherm describes the adsorption of ACC and BzC. From the application
of the Flory–Huggins isotherm, the number of water molecules displaced by the adsorbing inhibitor molecules was estimated.
The potential of zero charge pzc of mild steel without and with the inhibitors is calculated and the mechanism of corrosion inhibition is discussed in the
light of the molecular structure. 相似文献
11.
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
12.
M. S. Morad A. A. Hermas A. Y. Obaid A. H. Qusti 《Journal of Applied Electrochemistry》2008,38(9):1301-1311
Inhibition of low carbon steel (LCS) corrosion in 0.5 M H2SO4 solution by three bipyridinium dihalides (TMbPyBr2, HMbPyBr2 and MPhbPyCl2) was evaluated by potentiodynamic polarization curves, EIS and SEM techniques. The effectiveness of the inhibitors is ranked
as follows: MPhbPyCl2 ≅ TMbPyBr2 > HMbPyBr2. The compounds behave as mixed-type inhibitors and their adsorption on the steel surface obeys the Langmuir adsorption isotherm.
EIS measurements indicate that charge transfer controls the corrosion of steel in the absence and presence of the inhibitors
and the equivalent circuit Re(RctQdl) represents the electrode/solution interface either at the corrosion potential or at −75 and 30 mV versus Ecorr. The compounds show maximum inhibition efficiency at 35 °C. The mechanism of corrosion inhibition was discussed in the light
of the molecular structure of the bipyridinium salts. 相似文献
13.
I. Ahamad C. Gupta R. Prasad M. A. Quraishi 《Journal of Applied Electrochemistry》2010,40(12):2171-2183
This study investigates the effect of a Schiff base namely 2-[2-(2-(3-phenylallylidene)hydrazine carbonothioyl)hydrazinecarbonyl]benzoic
acid (SB), on corrosion inhibition of mild steel in 1 M HCl. Electrochemical impedance measurement, potentiodynamic polarization
and weight loss methods were applied to study adsorption of SB at metal/solution interface. Results revealed that SB is an
excellent inhibitor for mild steel corrosion in 1 M HCl; showing a maximum efficiency 99.5% at concentration of 1.36 × 10−6 M. Fourier transform infrared spectroscopy (FTIR) observations of the mild steel surface confirmed the formation of protective
film on the metal surface by studied compound. Polarization studies showed that SB is a mixed-type inhibitor. Adsorption process
obeyed Langmuir’s model with a standard free energy of adsorption (∆G°ads) of −46.7 kJ mol−1. Energy gaps for interactions between mild steel surface and inhibitor were found to be close to each other showing that
SB possess capacity to behave as both electron donor and acceptor. 相似文献
14.
M. F. L. Granero P. H. L. S. Matai I. V. Aoki I. C. Guedes 《Journal of Applied Electrochemistry》2009,39(8):1199-1205
This article describes a study of the behavior of a mixture of amines and amides, commercially known as Dodigen 213-N (D-213 N),
as a corrosion inhibitor for ASTM 1010 mild steel in 10% w/w HCl solution. The concentration range used was 1 × 10−5 M to 8 × 10−4 M. The weight loss and electrochemical techniques used were corrosion potential measurement, anodic and cathodic polarization
curves, and electrochemical impedance spectroscopy (EIS). The solution temperature was 50 ± 1 °C and it was naturally aerated.
The corrosion potential values shifted to slightly more positive values, thus indicating mixed inhibitor behavior. The anodic
and cathodic polarization curves showed that D-213 N is an effective corrosion inhibitor, since both the anodic and the cathodic
reactions were polarized in comparison with those obtained without inhibitor. For all concentrations the cathodic polarization
curves were more polarized than the anodic ones. The inhibition efficiency was in the range 75–98%, calculated from values
of weight loss and corrosion current density, i
corr, obtained by extrapolation of Tafel cathodic linear region. 相似文献
15.
A. Ousslim K. Bekkouch B. Hammouti A. Elidrissi A. Aouniti 《Journal of Applied Electrochemistry》2009,39(7):1075-1079
The inhibitory action of two piperazine derivatives, 1-benzyl piperazine (P1) and bis(1-benzylpiperazine) thiuram disulfide (P2) on the corrosion of mild steel in 3.9 M HCl at different concentrations has been
investigated in the temperature domain 298–333 K. Both weight loss measurements and potentiodynamic polarization methods showed
that P2 was the best inhibitor and that its inhibition efficiency increased with concentration to a value >92% at 10−3 M. Potentiodynamic polarization studies clearly revealed that P2 acts as cathodic-type inhibitor. The activation energy for
the corrosion rates was evaluated in the temperature range 298–333 K. Adsorption of P2 on the mild steel surface in 3.9 M
HCl followed a Langmuir isotherm model. A physical adsorption phenomenon is proposed. 相似文献
16.
M. S. Morad 《Journal of Applied Electrochemistry》2007,37(6):661-668
The corrosion resistance of mild steel in 1 M H2SO4 solution was evaluated after addition of Sn2+ and Zn2+, N-acetylcystein (ACC) and S-benzylcystein (BzC) as a function of concentration (5–1000 μM) and solution temperature (35–50°C). Eight blends were also
investigated. Both polarization resistance (R
p) and electrochemical impedance spectroscopy (EIS) were employed. For single additives, Zn2+ ions acted as accelerator for mild steel corrosion while the other additives showed good performance. The most effective
additive was Sn2+. Adsorption of Sn2+, ACC and BzC obeyed the Temkin adsorption isotherm and had a very high negative value of free energy of adsorption (−ΔG°ads). All blends provided good inhibition which increased with rise in temperature. Corrosion kinetic parameters such as activation
energy (E
a) and the pre-exponential factor (λ) were calculated and discussed. EIS revealed that the interface of the uninhibited and
inhibited systems can be represented by the simple equivalent circuit R
e(R
ct
Q
dl). 相似文献
17.
Mohammed A. Amin 《Journal of Applied Electrochemistry》2009,39(5):689-696
Polarization measurements were employed, as a first step towards studying the corrosion behaviour of Al and two Al–Cu alloys,
namely Al–4.5%Cu, and Al–7.5%Cu alloys in deaerated stirred 1.0 M H3PO4 solution at 25 °C. Inhibition of Al and Al–Cu alloys corrosion in 1.0 M H3PO4 solution, using sodium oleate (SO) as an anionic surfactant inhibitor, was also studied. Polarization curves showed that
SO acted as a mixed-type inhibitor to Al corrosion, while it acted mainly as a cathodic inhibitor to the acid corrosion of
Al–4.5%Cu, and Al–7.5%Cu alloys. Inhibition is accomplished by inhibitor adsorption on the electrode surface without detectable
changes in the chemistry of corrosion. The relationship between surfactant concentration, surfactant critical micellar concentration
(CMC), and corrosion inhibition is also discussed based on the Langmuir isotherm assumption, commonly applied in corrosion
inhibition evaluations. The protection efficiency increases with increase in surfactant concentration and %Cu in Al samples.
Maximum protection efficiency of the surfactant is observed at concentrations around its CMC. The mechanism of adsorption
is discussed based on the surface charge of the electrode surface. 相似文献
18.
Safaa El-din H. Etaiw Abd El-Aziz S. Fouda Said A. Amer Mohamed M. El-bendary 《Journal of Inorganic and Organometallic Polymers and Materials》2011,21(2):327-335
Yellow crystals of the metal–organic framework (MOF), [Ag(qox)(4-ab)] (1) were obtained at room temperature by the reaction of AgNO3, quinoxaline (qox) and 4-amino benzoic acid (4-aba). A cluster molecule containing two silver atoms, two qox and two 4-ab
ligands is considered the basic building block of the structure of 1. A 3D-network structure is created via H-bonds and π–π stacking. MOF 1 was tested as a corrosion inhibitor for C-steel in 1 M HCl solution using potentiodynamic polarization and electrochemical
impedance techniques. It was found that 1 is rich with electron donating groups and the π-systems exhibiting high inhibition efficiency. The adsorption of 1 obeyed the Freundlich adsorption isotherm. Polarization curves indicate that 1 is mixed-type inhibitor. Activation parameters were calculated and discussed. The results obtained from EIS and potentiodynamic
polarization are in good agreement. 相似文献
19.
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
20.
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