Inhibition of copper corrosion in aerated hydrochloric acid solution by amino-acid compounds

The effect of two amino-acid compounds, dl-alanine and dl-cysteine, on copper corrosion in an aerated 0.5 mol l⁻¹ HCl solution was studied by weight-loss measurements, potentiodynamic polarisation curves, and electrochemical impedance spectroscopy. A conventional benzotriazole (BTA) inhibitor was also tested for comparison. dl-cysteine was shown to be the most effective inhibitor among those tested inhibitors. Potentiodynamic polarisation results revealed that both the dl-alanine and dl-cysteine acted as an anodic inhibitor; however, dl-cysteine, in particular, was more effective, as it strongly suppressed anodic current densities. The improved inhibition efficiency of dl-cysteine in the 0.5 mol l⁻¹ HCl solution was due to its adsorption on the copper surface via the mercapto group in its molecular structure.     

Effect of some substituted anilines‐formaldehyde polymers on mild steel corrosion in hydrochloric acid medium

The influence of linear copolymer of amines and formaldehyde namely poly(aniline‐formaldehyde) (Inh1), poly(o‐toluidene‐formaldehyde) (Inh2), and poly(p‐chloroaniline‐formaldehyde) (Inh3) on corrosion of mild steel in hydrochloric acid was evaluated by weight loss measurements, linear polarization, Tafel polarization, and electrochemical impedance spectroscopy. These polymers showed very high inhibition efficiency at very low concentrations. Results obtained showed that all inhibitors are mixed inhibitors and participate in reaction probably in the form of metal inhibitor complex on metal surface. Atomic force microscopic studies reveal that the surface of metal is quite unaffected after use of inhibitor in hydrochloric acid solution. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Inhibition effect of some polymers on the corrosion of cadmium in a hydrochloric acid solution

The effects of poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), sodium polyacrylate (NaPA), poly(ethylene glycol) (PEG), pectin (P), and carboxymethyl cellulose (CMC) on the corrosion of cadmium in a 0.5M hydrochloric acid (HCl) solution were studied with both electrochemical impedance spectroscopy and Tafel plot techniques. Measurements were carried out at cathodic, open‐circuit, and anodic potentials. All the investigated polymers had inhibitory effects on both the cathodic (except for NaPA, P, and CMC) and anodic processes, with a predominant anodic inhibiting action. However, NaPA, P, and CMC exhibited a slight cathodic inhibiting action only at higher polymer concentrations. This behavior may be attributed to the very weak adsorbability of the polymers on the cathodic sites. Because PVA and PEG had hydroxy groups, there could be bridging between the polymer and the surface, resulting in an inhibiting effect in the HCl solution. However, PVA had much greater adsorbability on the surface than PEG at the anodic potential. The adsorption of most of the polymers obeyed a Temkin adsorption isotherm, and this indicated indicating that the main process of inhibition was adsorption. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 866–871, 2003     

Adsorption properties and inhibition of mild steel corrosion in hydrochloric acid solution by ceftobiprole

The inhibition effect of ceftobiprole against the corrosion of mild steel in 1 M HCl solution was studied by weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and atomic force microscopy techniques. Inhibition efficiency increased with inhibitor concentration where as decreased with acid concentration. Data obtained from EIS studies were analyzed to model the corrosion inhibition process through appropriate equivalent circuit models. The adsorption of ceftobiprole obeyed Langmuir adsorption isotherm. Both thermodynamic and activation parameters were calculated and discussed. Polarization curves indicated that they are mixed type of inhibitors. Polarization curves showed that ceftobiprole act as mixed-type inhibitor. The results obtained from weight loss, EIS and Potentiodynamic polarization are in good agreement.     

钼酸盐和钨酸盐在HCl中对冷轧钢的缓蚀作用

用失重法和动电位极化曲线法研究了在0．2mol／L HCl介质中,钼酸钠（Na2MoO4）、钨酸钠（Na2WO4）对冷轧钢片的吸附及其缓蚀作用。实验结果表明,在酸性溶液中,钼酸盐、钨酸盐均对冷轧钢片具有较好的缓蚀作用,而且用量很低。缓蚀剂在钢表面的吸附符合Langmuir吸附方程。在相同条件下,对比了钼酸钠、钨酸钠对冷轧钢的缓蚀作用,发现缓蚀率取决于缓蚀剂的质量浓度,当缓蚀剂浓度极低时缓蚀率排序为：钼酸钠〈钨酸钠,但在较大缓蚀剂质量浓度范围内钼酸钠表现出优越的缓蚀性能。动电位极化曲线表明,钼酸盐、钨酸盐在HCl中为混合抑制型缓蚀剂。     

Quantum chemical studies on corrosion inhibition for series of thio compounds on mild steel in hydrochloric acid

Quantum chemical calculations were performed on ten thio compounds using semi-empirical method PM3 within program package of Material Studio 5.5. The effect of molecular structure on the corrosion inhibition efficiency was investigated using the quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, (LUMO–HOMO) energy gap, dipole moment (λ) and fraction of electron transfer (ΔN) were calculated and discussed. A relationship between the corrosion inhibition efficiency and several quantum parameters was established with coefficient correlation (R²) of 0.8894.     

Experimental and theoretical study on amino acid derivatives as eco-friendly corrosion inhibitor on mild steel in hydrochloric acid solution

Amino acid derivatives, namely, 2-(2-oxo-2-phenothiazin-10-yl)ethylamino)-3-mercaptopropanoic acid (OPEM) and 2-(2-oxo-2-phenothiazin-10-yl)ethylamino)acetic acid (OPEA) were synthesized and investigated as inhibitors for mild steel corrosion in 15% HCl solution using the weight loss, polarization, and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiency of both the inhibitors increased with increasing the temperature and concentration of inhibitor. The inhibitors OPEM and OPEA show corrosion inhibition efficiency of 97.5 and 95.8%, respectively, in 200?ppm concentration, at 333?K. Polarization studies showed that both studied inhibitors were of mixed type in nature. The adsorption of inhibitors on the mild steel surface obeys Langmuir adsorption isotherm and the surface of inhibited and uninhibited specimens were analyzed by scanning electron microscopy (SEM). The semiempirical AM1 method was employed for theoretical calculations and the obtained results were found to be consistent with the experimental findings.     

Inhibiting effects of 5-substituted isatin-based Mannich bases on the corrosion of mild steel in hydrochloric acid solution

The inhibition effect of all the three Mannich bases against the corrosion of mild steel in 1 M HCl solution was studied by weight loss, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and atomic force microscopy techniques. Data obtained from EIS studies were analyzed to model the corrosion inhibition process through appropriate equivalent circuit models. The adsorption of Mannich bases obeyed Langmuir adsorption isotherm. Both thermodynamic and activation parameters were calculated and discussed. Polarization curves indicate that they are mixed type of inhibitors. All the Mannich bases were adsorbed physically at lower concentration, whereas chemisorption was favored at higher concentration. The results obtained from weight loss, EIS, and Potentiodynamic polarization are in good agreement.     

盐酸介质中碳钢缓蚀剂最新研究进展

碳钢是工业应用最广用途最大的一种钢材,在对它的表面处理中,盐酸的使用最多。本文从酸洗清洁生产的角度出发,对近几年研究的在盐酸介质中所使用的碳钢缓蚀剂进行了分类总结,并提出了现阶段研究中还需要重点考虑的问题,最后对缓蚀剂的研发做出了展望。     

Experimental and theoretical study of xanthene derivatives as corrosion inhibitor for mild steel in hydrochloric acid solution

Journal of Applied Electrochemistry - The present paper aims to synthesize and examine the adsorption of a novel heterocyclic compound of xanthene derivatives, namely...     

硝酸根离子对铝在盐酸溶液中的缓蚀作用

用失重法和动电位极化曲线方法研究了硝酸根离子对工业纯铝在1．5mol／L HCl溶液中的缓蚀作用和机理,讨论了其在铝表面的吸附。结果表明,对铝在盐酸溶液中的腐蚀,硝酸根离子是很一种很好的缓蚀剂。当硝酸根离子浓度较低时,其缓蚀效率随着浓度增加而增大,随后增加硝酸根离子,缓蚀效率基本稳定;当硝酸根离子浓度较大时,缓蚀效率在测量时间内随着腐蚀时间的延长而增大。硝酸根离子通过抑制铝的阴极反应而起到缓蚀作用,其在铝表面的吸附符合Freundlich吸附等温式。     

盐酸溶液中香兰素在钢表面的吸附及缓蚀作用

用失重法和动电位极化曲线法研究了香兰素(4-羟基-3-甲氧基-苯甲醛)在1.0 mol/L HCl中20～50℃下在冷轧钢表面上的吸附及缓蚀作用.结果表明:香兰素在HCl中为阴极抑制型缓蚀剂,缓蚀率随香兰素的浓度增加而增大,而随温度的增加而减小;香兰素在钢表面的吸附符合Temkin吸附模型.通过吸附理论求出了相应的吸附热力学参数(吸附自由能ΔGo,吸附热ΔHo,吸附熵ΔSo),并根据这些参数详细讨论了缓蚀作用机理.     

盐酸中原儿茶醛在钢表面的吸附及缓蚀作用

用失重法和动电位极化曲线法研究了在1.0mol/L HCl中20~50℃原儿茶醛(3,4-二羟基苯甲醛)在冷轧钢表面上的吸附及缓蚀作用.结果表明:原儿茶醛具有中等程度的缓蚀作用,为混合抑制型缓蚀剂,缓蚀率随原儿茶醛的浓度增加而增大,但随温度的增加而减小;原儿茶醛在钢表面的吸附符合Freundlich吸附模型.通过吸附理论和动力学Arrhenius公式求出了相应的吸附热力学参数(吸附自由能ΔG°,吸附热ΔH°,吸附熵ΔS°)和动力学参数表观活化能Ea,并根据这些参数详细讨论了缓蚀作用机理.     

表面活性剂在HCl中对钢的缓蚀协同效应

用失重法和电化学法研究了在1.0 mol/L HCl中阴离子表面活性剂油酸钠(SO)和非离子表面活性剂聚乙二醇辛基苯基醚(OP)对冷轧钢的缓蚀协同作用.研究结果表明,单独的SO和OP对冷轧钢具有一定的缓蚀作用,为混合型缓蚀剂,且在钢表面的吸附符合Temkin吸附模型.当两者复配后产生了明显的缓蚀协同效应,最大缓蚀率可达92%.     

Effect of ethylenediamine tetraacetic acid disodium on the corrosion of cold rolled steel in the presence of benzotriazole in hydrochloric acid

The inhibition behavior of cold rolled steel in 0.1 M hydrochloric acid (HCl) by ethylenediamine tetraacetic acid disodium (EDTA) in the absence and presence of benzotriazole (BTA) was investigated with Tafel polarization curve and electrochemical impedance spectroscopy (EIS). The polarization curve results show that the single EDTA acts as an anodic type inhibitor while the combination of EDTA and BTA acts as mixed type inhibitor and mainly inhibits anodic reaction. All impedance spectra in EIS tests exhibit one capacitive loop which indicates that the corrosion reaction is controlled by charge transfer process. Inhibition efficiencies obtained from Tafel polarization, charge transfer resistance (R_t) are consistent. The corrosion of cold rolled steel in 0.1 M HCl is obviously reduced by EDTA in combination with lower concentrations of BTA. Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM) were used to characterize the corrosion surface of cold rolled steel. Probable mechanisms are present to explain the experimental results.     

Ceftriaxone: a novel corrosion inhibitor for mild steel in hydrochloric acid

Corrosion inhibition of mild steel in 1 N HCl by Ceftriaxone was studied by polarization resistance, Tafel polarization, EIS, and weight loss measurement. The inhibitor showed more than 90% inhibition efficiency at optimum concentration of 400 ppm. Results obtained revealed that inhibition occurs through adsorption of the drug on the metal surface without a modification of the mechanism of the corrosion process. Potentiodynamic polarization suggests that this is a mixed type of inhibitor. Electrochemical impedance spectroscopy was used to investigate the mechanism of corrosion inhibition. Thermodynamic parameters such as E _a, ΔH, ΔS, ΔG and Q were calculated to investigate the mechanism of inhibition. All the investigations suggested that the compound follows the Langmuir adsorption isotherm.     

盐酸中烯丙基硫脲在钢表面的吸附及缓蚀作用

用失重法研究了在1.0 mol/L 盐酸中20～50℃烯丙基硫脲(ATU)在冷轧钢表面上的吸附及缓蚀作用.结果表明:ATU对钢具有良好的缓蚀作用,在钢表面的吸附符合Langmuir吸附模型.通过吸附理论和动力学Arrhenius公式分别求出了相应的吸附热力学参数(吸附自由能△G°, 吸附热△H°, 吸附熵△S°)和动力学参数表观活化能Ea,并根据这些参数详细讨论了缓蚀作用机理.     

盐酸溶液中二乙烯三胺对黄铜的缓蚀作用及吸附热力学研究

采用失重法研究了不同温度下不同浓度的二乙烯三胺在10%的盐酸介质中对黄铜的缓蚀作用.结果表明,二乙烯三胺在10%的盐酸介质中对黄铜的脱锌腐蚀有良好的抑制作用,二乙烯三胺在黄铜表面的吸附规律基本服从Langmuir等温式,由此获得相关热力学参数.     

Corrosion inhibition effect of pyrazole derivatives on mild steel in hydrochloric acid solution

Synthesized compounds, namely methyl 5-(4-Chlorobenzoyloxy)-1-phenyl-1H-pyrazole-3-carboxylate (MCPPC) and 5-(4-methoxyphenyl)-3-(4-methylphenyl)4,5-dihydro-1H-pyrazol-1-yl-(pyridin-4-yl)methanone (MMDPPM) were investigated as corrosion inhibitor for mild steel (MS) in 15% HCl solution using weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods. Inhibition efficiency was found concentration-dependent and increased by increasing the concentration of MCPPC and MMDPPM. Both of inhibitors were efficient even at a very low concentration of 25 ppm. The inhibitors MCPPC and MMDPPM showed inhibition efficiency of 67.1 and 76.8%, respectively, at 25 ppm, whereas it was 92.0 and 95.9%, respectively, at 250 ppm concentration at 303 K. The potentiodynamic polarization curves showed that MCPPC and MMDPPM act as mixed-type inhibitor in 15% HCl solution. The Nyquist plots showed that charge transfer resistance increased and double-layer capacitance decreased on increasing the concentration of studied inhibitors due to adsorption of inhibitor molecules on MS surface. The adsorption of each inhibitor on MS surface obeys Langmuir adsorption isotherm. On the basis of thermodynamic adsorption parameters, mixed-type adsorption (physisorption and chemisorption) for the studied inhibitors on MS surface was suggested. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and atomic force microscopy (AFM) analyses confirmed the existence of a protective film of the inhibitor on MS surface. The density functional theory was employed for theoretical calculations, and the obtained results were found to be consistent with the experimental findings.     

吐温-85对冷轧钢在盐酸溶液中的缓蚀性能

用失重法研究了吐温-85(聚氧乙烯山梨醇三油酸酯)对冷轧钢在盐酸溶液中的缓蚀作用,详细考察了缓蚀剂质量浓度(10～100mg/L)、温度(20～50℃)、腐蚀浸泡时间(6～144h)和盐酸浓度(1.0～8.0mol/L)对缓蚀性能的影响.结果表明:吐温-85对冷轧钢在1.0mol/L HCl溶液中具有良好的缓蚀作用,缓蚀率随缓蚀剂质量浓度的增加而增大,但随温度和盐酸浓度的增加而减小.通过Arrhenius公式和Mathur经验动力学公式分别求出了相应的腐蚀动力学参数(表观活化能Ea, 指前因子A,速率常数k, 动力学常数B),并根据这些参数讨论了吐温-85的缓蚀行为.