Corrosion inhibition of 302 stainless steel with schiff base compounds

The effects of 2,2′-[bis-N(4-cholorobenzaldimin)]-1,1′-dithio (BCBD) and bis-(2-aminophenyl) disulphide (BAPD) on the corrosion behavior of 302 stainless steel in 0.5 M sulfuric acid solution as corrosive medium were investigated using weight loss and potentiostatic polarization techniques. Some corrosion parameters such as anodic and cathodic Tafel slopes, corrosion potential, corrosion current density, surface coverage degrees and inhibition efficiencies were calculated. The polarization measurements indicated that the inhibitors were of mixed type which inhibited corrosion by parallel adsorption on the surface of stainless steel due to the presence of more than one active centre in the inhibitor molecule. The adsorption followed Langmuir adsorption isotherm. The activation energy and thermodynamic parameters were calculated at different temperatures. Results showed that BCBD had a higher inhibition efficiency compared with BAPD.     

Inhibition effect of butan-1-ol on the corrosion behavior of austenitic stainless steel (Type 304) in dilute sulfuric acid

The electrochemical behavior of austenitic stainless steel (Type 304) in 3 M sulfuric acid with 3.5% recrystallized sodium chloride at specific concentrations of butan-1-ol was investigated with the aid of potentiodynamic polarization, open circuit measurement and weight loss technique. Butan-1-ol effectively inhibited the steel corrosion with a maximum inhibition efficiency of 78.7% from weight-loss analysis and 80.9% from potentiodynamic polarization test at highest concentration studied. Adsorption of the compound obeyed the Freundlich isotherm. Thermodynamic calculations reveal physiochemical interactions and spontaneous adsorption mechanism. Surface characterizations showed the absence of corrosion products and topographic modifications of the steel. Statistical analysis depicts the overwhelming influence and statistical significance of inhibitor concentration on the inhibition performance.     

Detergent-Induced Removal of beta-Lactoglobulin from Stainless Steel Surfaces as Influenced by Surface Pretreatment

The adsorption of beta-lactoglobulin to stainless steel and its subsequent removal were followed using in situ null ellipsometry. The influence of the surface pretreatment on the protein removal by the surfactant SDS and by sodium hydroxide was studied. All surfaces were precleaned in strongly alkaline solution. Some surfaces received no further pretreatment, while others were either passivated in nitric acid or plasma-cleaned prior to experiments. Stainless steel surfaces subjected to different surface pretreatments showed considerable differences in cleaning behavior. Cleaning, using NaOH, of surfaces which had been precleaned with alkali only or with plasma resulted in practically complete beta-lactoglobulin removal. In contrast, appreciable amounts of protein remained on passivated stainless steel. Protein removal by SDS was limited and comparable for all three surface pretreatments investigated. Only minor effects on the protein adsorption tendency were observed. The amounts of beta-lactoglobulin adsorbed tended to be somewhat lower on the passivated surfaces. Copyright 1999 Academic Press.     

Contribution of acidic amino residues to the adsorption of peptides onto a stainless steel surface

The role of the acidic amino acid residues in the adsorption of peptides/proteins onto stainless steel particles was investigated using a peptide fragment from bovine beta-lactoglobulin, Thr-Pro-Glu-Val-Asp-Asp-Glu-Ala-Leu-Glu-Lys (T5 peptide), which has a high affinity to a stainless steel surface at acidic pHs, and its mutant peptides substituted with different numbers of acidic amino acid residues. The adsorption behavior of the mutant peptides as well as the T5 peptide were studied at pH 3 with respect to concentration and ionic strength dependencies and the reversibility of the adsorption process. The behavior of the peptides was generally characterized as two distinct irreversible adsorption modes, Mode I and Mode II. In Mode I, the amounts adsorbed lay on the ordinate at zero equilibrium concentration in the solution, while in Mode II, the amount adsorbed increased with increased equilibrium concentration. The area occupied by the peptides was predicted by molecular mechanics and molecular dynamics. The state of the peptides, when adsorbed, was investigated using FT-IR analysis. The FT-IR analyses revealed that the side carboxylic groups of the peptides adsorbed on the stainless steel surface were ionized, while they were unionized in the solution at pH 3. Thus, the interactions between the carboxylic groups of the peptide and the stainless steel surface can be considered to be largely electrostatic. The peptide having four acidic amino acid residues took a maximum adsorbed amount, the reason for which is discussed.     

绿色聚天冬氨酸复配缓蚀剂对A3碳钢的缓蚀抑雾作用

采用失重法和极化曲线法研究了聚天冬氨酸(PASP)和十二烷基酚聚氧乙烯醚(OP-10)复配对A3碳钢在6mol·L-1HCl腐蚀介质中的协同吸附行为及缓蚀抑雾作用.结果表明:复配缓蚀剂可有效抑制A3碳钢在HC1介质中的腐蚀,当PASP浓度为20g·L-1,缓蚀率可达94%,抑雾率83%;随着温度的升高,复配缓蚀剂的缓蚀性能下降.复合缓蚀剂在钢表面的吸附符合校正的Langmuir模型,吸附过程为放热、熵减的自发过程;复配体系属于阳极型缓蚀剂.     

Thermodynamic and adsorption behavior of N<Subscript>2</Subscript>O<Subscript>4</Subscript> schiff base as a corrosion inhibitor for API-5L-X65 steel in HCl solution

The inhibition ability of N,N′-bis(2,4-dihydroxyacetophenone)-1,3-propandiimine (DHAPP) as a schiff base against the corrosion of API-5L-X65 in 1 M HCl solution was evaluated by polarization, electrochemical impedance spectroscopy, and scanning electron microscopy. Polarization studies indicated that DHAPP retards both the cathodic and anodic reactions through chemical adsorption and blocking the active corrosion sites. The adsorption of this compound obeyed the Langmuir adsorption isotherm. The inhibition efficiency increased with inhibitor concentration and decreased with increasing temperature. EIS data analysed to equivalent circuit model showed that as the inhibitor concentration increased the charge transfer resistance of steel increased whilst double layer capacitance decreased. Kinetic and thermodynamic parameters such as activation energy, enthalpy, entropy, and Gibbs free energy of activation and adsorption were calculated. Gibbs free energy indicated that adsorption occurred through physical and spontaneous process. Scanning electron microscopy was used to study the steel surface with and without inhibitor.     

Theoretical and experimental approach of inhibition effect by sulfamethoxazole on mild steel corrosion in 1‐M HCl

The inhibition effect of sulfamethoxazole on mild steel corrosion in 1‐M hydrochloric acid solution is investigated by electrochemical and quantum chemical measurements. Electrochemical polarization studies show that sulfamethoxazole acts as a mixed‐type corrosion inhibitor. The adsorption of the inhibitor on mild steel in 1‐M hydrochloric acid system is studied at different temperatures (303‐333 K). The adsorption of sulfamethoxazole on mild steel surface is an exothermic process and obeys the Temkin adsorption isotherm. Based on the potential of zero charge values and quantum chemical parameters, the mechanism of adsorption is proposed.     

Berberine isolated from Mahonia nepalensis as an eco-friendly and thermally stable corrosion inhibitor for mild steel in acid medium

BackgroundThe environmental and economic benefits have been the driving force in search of efficient corrosion inhibitors for iron/steel used in industrial acidic medium. This study reports on berberine isolated from methanol extract of high-altitude (1347 m) shrub Mahonia nepalensis as a highly efficient and thermally stable corrosion inhibitor for mild steel (MS) in 1.0 M H₂SO₄ simulating acid pickling condition.MethodsThe weight-loss and electrochemical methods revealed the fast adsorption of berberine.Significant Findings: It achieved above 91% inhibition efficiency (IE) in 0.25 h and reached 94% in 6 h for 1000 ppm berberine. The IE increased with concentration and temperature, giving an IE of 97.2% at 328 K, which makes it a promising candidate for industrial application. It behaved as a mixed type of inhibitor as revealed by open circuit potential and polarization curves. The results indicated suppression of the corrosion by effectively forming an adsorbed berberine layer on the MS surface. Adsorption of the berberine followed a Langmuir adsorption isotherm. The thermodynamic parameters such as activation energy (43.19 kJ/mol), free energy (−35.05 kJ/mol), enthalpy (40.55 kJ/mol), and entropy (−97.83 J/molK) of adsorption supported both physical and chemical interactions of berberine with MS surface. The obtained results also revealed that the adsorption process was endothermic and spontaneous in nature.     

Inhibition of acid corrosion of carbon steel using aqueous extract of olive leaves

The inhibitive action of the aqueous extract of olive (Olea europaea L.) leaves toward the corrosion of C-steel in 2 M HCl solution was investigated using weight loss measurements, Tafel polarization, and cyclic voltammetry. It was found that the extract acts as a good corrosion inhibitor for the tested system. The inhibition efficiency increases with increasing extract concentration. The inhibitive action of the extract is discussed with a view to adsorption of its components onto the steel surface, making a barrier to mass and charge transfer. The adsorption of extract components onto the steel surface was found to be a spontaneous process and to follow the Langmuir adsorption isotherm. It was found also that such adsorption increases the activation energy of the corrosion process. The results of cyclic voltammetry showed that the presence of olive extract decreases the charge density in the transpassive region. The inhibition efficiency is greatly reduced as the temperature is increased.     

Hydroclathrus clathratus marine alga as a green inhibitor of acid corrosion of mild steel

The corrosion inhibitive and adsorption behaviors of Hydroclathrus clathratus on mild steel in 1 M HCl and 1 M H₂SO₄ solutions at 303, 313 and 323 K were investigated by weight loss, electrochemical, and surface analysis techniques. The results show that H. clathratus acts as an inhibitor of corrosion of mild steel in acid media. The inhibition efficiency was found to increase with increase in inhibitor concentration but to decrease with rise in temperature, suggestive of physical adsorption. The adsorption of the inhibitor onto the mild steel surface was found to follow the Temkin adsorption isotherm. The inhibition mechanism was further corroborated by the results obtained from electrochemical methods. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses supported the inhibitive action of the alga against acid corrosion of mild steel.     

A cyclic voltammetry study of the adsorption of alcohol dehydrogenase (HLADH) onto a platinum electrode

A cyclic voltammetry study of the interfacial behaviour of horse liver alcohol dehydrogenase (HLADH) at a Pt surface in a phosphate buffer solution pH 7.0 over the temperature range 273 to 353 K is presented. The surface charge density, resulting from protein adsorption, was shown to be directly proportional to the amount of adsorbed protein (surface concentration). HLADH exhibits very high affinity towards adsorption onto a Pt surface via chemisorption. The Langmuir isotherm was employed for modeling the adsorption process and the values of the Gibbs free energy, enthalpy and entropy of adsorption were calculated. The thermodynamic data suggested that disruption of tertiary structure of the protein occurs upon adsorption at the Pt surface and that the breaking of intramolecular interactions during the adsorption governs the rate of the process.     

Pitting inhibition of stainless steel by surfactants: an electrochemical and surface chemical approach

Pitting corrosion of stainless steels causes tremendous damage in terms of material loss and resulting accidents. Organic surfactants have been tried as pitting inhibitors but the understanding of the inhibition mechanisms is mainly speculative. In the present study the inhibition of the pitting corrosion of 304 stainless steel by N-lauroylsarcosine sodium salt (NLS) in 0.1 M NaCl solutions at neutral pH was studied using an approach that combines surface chemical techniques with electrochemical ones. It was found that NLS increases the pitting resistance of 304 stainless steel, with possible complete inhibition at high NLS concentration (30 mM). Adsorption of NLS on 304 stainless steel particles was directly measured. NLS adsorbs significantly on 304 stainless steel with maximum adsorption density close to bilayer coverage. Electrophoretic mobility data for 304 stainless steel particles show that the surface of 304 stainless steel is negative in NaCl solution at neutral pH. The adsorption of NLS makes the interfacial charge even more negative. The relationship between pitting inhibition and adsorption density of NLS suggests that NLS does not adsorb preferentially on the pit nucleation sites and complete inhibition requires that the whole surface be covered completely by NLS. The inhibition mechanism of NLS is proposed to be due mainly to the blocking effect of a negatively charged NLS adsorption layer. This study shows that in addition to the adsorption amount of surfactant, interfacial charge also plays an important role in pitting inhibition.     

天然海水中聚吡咯膜的防微生物附着及防腐蚀性能

采用恒电流法在316 L不锈钢电极表面合成聚吡咯(PPy), 通过开路电位、 生物显微镜(BM)、 Tafel极化曲线及电化学交流阻抗(EIS)研究了聚吡咯防止微生物附着及防腐蚀特性. 研究表明, 沉积聚吡咯的316 L不锈钢电极浸泡在天然海水中(0~20 d), 开路电位基本保持不变, 表明电化学合成的聚吡咯膜有良好的防止微生物附着能力, 并通过生物显微镜进行了验证, 且在浸泡的过程中其腐蚀电流密度维持在10^-7 mA/cm², 表现出良好的防腐蚀特性; 浸泡50 d后, 其防腐蚀效率仍高达97.45%. 因此, 电化学合成的聚吡咯具有优异的防止微生物附着和防腐蚀特性.     

Role of novel oxazocine derivative as corrosion inhibitor for 304 stainless steel in acidic chloride pickling solutions

Inhibition of 304 stainless steel corrosion in acidic chloride pickling (1.0 M HCl) solutions by newly synthesized oxazocine derivative 4 as a corrosion inhibitor have been studied using weight loss, potentiodynamic polarization, and atomic absorption spectroscopy investigations. Potentiodynamic polarization curves show that the inhibitor behaves as a mixed-type. The adsorption of the inhibitor on the metal surface in the acid solution was found to obey Langmuir’s adsorption isotherm. The inhibition mechanism of the investigated inhibitor was discussed in terms of its adsorption on the metal surface. The relationship between the molecular structure and the inhibition efficiency was elucidated by quantum chemical calculations.     

Synergistic and antagonistic effects between halide ions and carboxymethyl cellulose for the corrosion inhibition of mild steel in sulphuric acid solution

The corrosion and corrosion inhibition effect of carboxymethyl cellulose (CMC) for mild steel in sulphuric acid medium was investigated using chemical (weight loss and hydrogen evolution) techniques at 30–60 °C. The effect of addition of halide ions (Cl⁻, Br⁻, and I⁻) was also studied. It was found that CMC functions as an inhibitor for acid induced corrosion for mild steel. Inhibition efficiency increases with increase in immersion time but decreases with increase in temperature. Addition of halide ions reveals that chloride ions (Cl⁻) antagonize the inhibition process whereas iodide ions (I⁻) exert synergistic effect on the corrosion inhibition by CMC. Corrosion inhibitive effect was afforded by adsorption of CMC molecules onto the mild steel surface both in the absence and presence of halide ions which was found to follow Langmuir adsorption isotherm model. The phenomenon of physical adsorption is proposed from decrease in inhibition efficiency with increase in temperature. The inhibition mechanism was further corroborated by the values of thermodynamic and kinetic parameters obtained from the experimental data.     

Study of the adsorption of fibrinogen on gold-coated silicon wafer by an impedance method

In 0.1 mol/l KH(2)PO(4)-Na(2)HPO(4) (pH 7.80) buffer solution, the potential of zero charge (PZC) and the open circuit potential of gold-coated silicon were determined to be about -0.6 and +0.10 V (vs SCE), respectively. The open circuit potential was higher than the PZC, which indicated that the surface of the gold-coated electrode had a positive charge. The ellipsometry experiment showed that the adsorption of fibrinogen onto the gold-coated silicon wafer surface arrived at a saturated state when the adsorption time exceeded 50 min. The percentage of surface without adsorbed protein, theta, was about 63%. This means that the proportion of surface actually occupied by fibrinogen was only about 37% after the adsorption arrived at saturation. The solution/protein capacitance value was determined in an impulse state around -0.59 V (vs SCE) and was stable (4.2x10(-5) F) at other potentials.     

二硫代酰胺类化合物在盐酸中对碳钢的缓蚀性能(英文)

采用失重实验,动电位极化,交流阻抗,量子化学计算和拉曼光谱等方法研究了N,N′-二异丙氧基丙基二硫代二丙酰胺(DPDA)在1 mol.L-1盐酸溶液中对碳钢的缓蚀性能.失重实验结果表明,DPDA在盐酸溶液中能够有效地抑制碳钢的腐蚀,当缓蚀剂DPDA的浓度为1×10-3 mol.L-1时,其缓蚀效率达到90.2%.极化曲线表明DPDA为混合型缓蚀剂,单一的容抗弧变化表明碳钢电极表面的腐蚀过程主要由电荷转移步骤控制.由失重实验,动电位极化和电化学交流阻抗方法得到的DPDA缓蚀效率具有较好的相关性,均表现为缓蚀效率随着DPDA浓度的增大而增加.另外,DPDA在碳钢表面的吸附符合Langmuir吸附等温式.吸附过程的吉布斯自由能(ΔG0a0d0s)为-38.65 kJ.mol-1,这说明DPDA分子在碳钢表面形成共价键而发生了自发的化学吸附.拉曼光谱表明DPDA分子有效地吸附在碳钢表面,量子化学计算结果证明DPDA分子在碳钢表面的化学吸附活性中心集中在S原子上.     

A study on the electrochemical polymerization, characterization, and corrosion protection of o-toluidine on steel

Poly(o-toluidine) (POT) coatings were electrochemically synthesized on 304 stainless steel using cyclic voltammetric method. These coatings were characterized by Fourier transform infrared spectroscopy, UV–vis absorption spectroscopy, and cyclic voltammetry. The corrosion performance of POT coating in aqueous 3 wt% sodium chloride was assessed by the electrochemical techniques such as open circuit potential measurements, potentiodynamic polarization technique, cyclic potentiodynamic polarization measurements, and electrochemical impedance spectroscopy. The results reveal that POT coating on 304 stainless steel prevents general and localized corrosion, and reduces the exchange current density almost by a factor of 45 than bare 304 stainless steel.     

In situ SERS study of the adsorption of inhibitors of carbon dioxide corrosion

A specially designed electrochemical cell incorporating a rotating disc electrode has been used for in situ surface‐enhanced Raman spectroscopy (SERS) studies of the adsorption of inhibitors of carbon dioxide corrosion onto silver‐coated mild steel electrodes. It is shown that SERS‐active inhibitors comprising aromatic moieties may be detected using the SERS technique. Furthermore, the efficacy of adsorption of corrosion inhibitors employed in the present study is optimal near the open cell or corrosion potential, demonstrating that electrode polarization induces electrostatic forces of repulsion that retard the adsorption of the inhibitor to the corroding steel surface. Copyright © 2003 John Wiley & Sons, Ltd.     

Investigation on corrosion inhibition effect of N-[4-(1,3-benzo[d]thiazol-2-ylcarbamoyl)phenyl]quinoline-6-carboxamide as a novel organic inhibitor on mild steel in 1N HCl at different temperatures: Experimental and theoretical study

A new novel organic corrosion inhibitor N-[4-(1,3-benzo[d]thiazol-2-ylcarbamoyl)phenyl]quinoline-6-carboxamide (NBCPQC) has been synthesized. The synthesized novel organic inhibitor NBCPQC used to be carried out on mild steel corrosion in 1N HCl for the first time. The studied inhibitor was once evaluated as corrosion inhibitor for mild steel in 1N of HCl solution using electrochemical research which advocated that a protective film is form by the process of inhibitor absorption on the surface of mild steel. Inhibitor shows a better inhibiton efficiency of maximum above 90% in 1N HCl medium. Inhibitors show a better efficiency by way of reducing and sluggish down the corrosion process however on growing the temperature it is weakened on controlling corrosion. In addition to this adsorption isothermal models had been interpreted to fit the adsorption behaviour of the inhibitor compound on mild steel surface. Thus the result reveals that the compound shows a Langmuir adsorption isotherm.