2-氨基嘧啶在盐酸介质中对钢的缓蚀性能

用失重法、动电位极化曲线和电化学阻抗谱（EIS）研究了2-氨基嘧啶(2-AP)在1.0~5.0 mol/L HCl溶液中（20~50 ℃）对冷轧钢的缓蚀作用。 结果表明,2-AP对冷轧钢在1.0 mol/L HCl中具有良好的缓蚀作用,且在钢表面的吸附符合校正的Langmuir吸附模型;缓蚀率随缓蚀剂浓度的增加而增大,但随温度的升高和HCl浓度的增加而降低。 2-AP为混合抑制型缓蚀剂;EIS谱呈半圆容抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大。     

Inhibitive effect of imidazopyridine derivative towards corrosion of C38 steel in hydrochloric acid solution

The effect of adding 2-phenylimidazo[1,2-a]pyridine-3-carbaldehyde derivative named (P2), newly synthesized on the electrochemical behavior of C38 steel in molar hydrochloric acid was investigated by using the weight-loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) measurements. EIS results show that the transfer resistance increases with the increase of concentration of P2 and it also had an inhibiting effect on C38 steel corrosion in HCl solutions. Weight-loss essays confirm that the corrosion rate decreases as the P2 concentration increases. The inhibition efficiency for this compound studied increased with the increase in the inhibitor concentrations to attain 91.7 % at the 10^?3 M of P2. The potentiodynamic polarization curves indicated that P2 acted as a mixed-type inhibitor in hydrochloric acid.     

On the corrosion inhibition of iron in hydrochloric acid solutions,Part I: Electrochemical DC and AC studies

The inhibitive action of 4-methyl pyrazole (4MP) against the corrosion of iron (99.9999%) in solutions of hydrochloric acid has been studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). At inhibitor concentration range (10^?3–10^?2 M) in 1.0 M acid, the results showed that 4MP suppressed mainly the anodic processes of iron corrosion in 1.0 M HCl by adsorption on the iron surface according to Temkin adsorption isotherm. Both potentiodynamic and EIS measurements reveal that 4MP inhibits the iron corrosion in 1.0 M HCl and that the efficiency increases with increasing inhibitor concentration. Data obtained from EIS were analyzed to model the corrosion inhibition process through an equivalent circuit.     

Influence of pyridazine derivative on corrosion inhibition of mild steel in acidic media

The inhibition behavior of 6-methyl-4,5-dihydropyridazin-3(2H)-one (MDP) on corrosion of mild steel in 1 M HCl and 0.5 M H₂SO₄ was investigated using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) measurements. The results indicated that the corrosion inhibition efficiency depends on concentration, immersion time, solution temperature, and the nature of the acidic solutions. It is also noted that MDP is at its the most efficient in 1 M HCl and least in 0.5 M H₂SO₄. The effect is more pronounced with MDP concentration. It is found that the inhibition efficiency attains 98 % at 5 × 10^?3 M in 1 M HCl and 75 % at 5 × 10^?2 in 0.5 M H₂SO₄. Polarization measurements showed that the MDP acts as a mixed inhibitor. EIS diagrams showed that the adsorption of MDP increases the transfer resistance and decreases the capacitance of the interface metal/solution. From the temperature studies, the activation energies in the presence of MDP were found to be superior to those in uninhibited medium. Finally, a mechanism for the adsorption of MDP was proposed and discussed.     

Inhibitive effect by extract of Mentha rotundifolia leaves on the corrosion of steel in 1 M HCl solution

An extract of Mentha rotundifolia leaves (EMRL) was tested as a corrosion inhibitor of steel in 1 M HCl using electrochemical impedance spectroscopy, Tafel polarization methods, and weight loss measurements. The inhibition efficiency of the extract of Mentha rotundifolia leaves was calculated and compared. We note good agreement between these methods. The results obtained revealed that the inhibitor tested differently reduced the kinetics of the corrosion process of steel. Its efficiency increases with the concentration and attained 92.87 % at 35 %. The effect of temperature on the corrosion behavior of steel in 1 M HCl was also studied in the range 298 and 338 K. The thermodynamic data of activation were determined. Mentha rotundifolia extract is adsorbed on the steel surface according to a Langmuir adsorption model.     

药物莫西沙星对Q235钢在盐酸溶液中的缓蚀作用

为了探寻新的环境友好型缓蚀剂,采用电化学方法、失重法和量子化学计算研究了莫西沙星在1 mol/L HCl溶液中对Q235钢的缓蚀性能和缓蚀机理。结果表明,莫西沙星对Q235钢在盐酸溶液中是一种良好的以抑制阴极为主的混合抑制型缓蚀剂,缓蚀效率随其浓度的增加而增大,但随温度增加而减小,35℃下,在其浓度为200 mg/L时,缓蚀效率达90%;莫西沙星在Q235钢表面的吸附为自发过程,且符合Langmuir和El-Awady等温方程,同时,计算和讨论了相关的热力学和动力学参数。此外,采用量子化学计算对莫西沙星的缓蚀机理进行了进一步的分析,结果发现,莫西沙星的缓蚀作用由物理吸附和化学吸附共同产生。     

嘧啶衍生物对钢在盐酸溶液中的缓蚀作用

采用失重法、动电位极化曲线、电化学阻抗谱(EIS)、量子化学计算研究了两种嘧啶衍生物(2-羟基嘧啶(HP)和2-巯基嘧啶(MP))在1.0-5.0 mol·L^-1 HCl溶液中对冷轧钢(CRS)的缓蚀作用. 结果表明: HP和MP在1.0 mol·L^-1 HCl溶液中对冷轧钢具有良好的缓蚀作用, 且在钢表面的吸附符合Langmuir吸附等温式. 缓蚀率随缓蚀剂浓度的增加而增大, 但随盐酸浓度的增加而减小.求出了相应的吸附热力学参数(吸附平衡常数(K),吸附自由能(ΔG⁰))和腐蚀动力学参数(表观活化能(E_a)、指前因子(A)、腐蚀速率常数(k)、动力学常数(B)), 并根据这些参数讨论了缓蚀作用机理. 动电位极化曲线表明, MP和HP均为混合抑制型缓蚀剂; EIS谱呈单一容抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大. 两种嘧啶化合物的缓蚀率排序为MP>HP. 量子化学计算结果表明,MP比HP更具吸附活性,缓蚀性能的理论计算和实验结果相一致.     

Inhibition of mild steel corrosion in HCl solution using chitosan

The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild steel in 0.1 M HCl was investigated by gravimetric, potentiodynamic polarization, electrochemical impedance spectroscopy measurements, scanning electron microscopy, and UV–visible analysis. The polymer was found to inhibit corrosion even at a very low concentration. Inhibition efficiency increases with a rise in temperature up to 96 % at 60 °C and then drops to 93 % at 70 °C, while it slightly increases with an increase in chitosan concentration. Polarization curves indicate that chitosan functions as a mixed inhibitor, affecting both cathodic and anodic partial reactions. Impedance results indicate that chitosan was adsorbed on the metal/solution interface. Adsorption of chitosan at the mild steel surface is found to be in agreement with Langmuir adsorption isotherm model. Chemical adsorption is the proposed mechanism for corrosion inhibition considering the trend of protection efficiency with temperature. Calculated kinetic and thermodynamic parameters corroborate the proposed mechanism.     

MPEC-IMI as an effective green inhibitor to protect Q235 steel in 0.5 M HCl medium

Imidazole (IMI)-based polyethylene glycol monomethyl ether (MPEC-IMI) as a novel green corrosion inhibitor was synthesized to protect the Q235 steel in 0.5 M HCl corrosive medium at 318 K. The inhibition performance of MPEC-IMI was investigated by weight loss measurement, the electrochemical method (Tafel and EIS) and surface analysis (SEM and EDX). The results reveal that the MPEC-IMI shows enhanced anticorrosion performance for carbon steel, which is attributed to the formation of the adsorptive protection film on the surface, and the type of adsorption basically obeys the Langmuir monolayer adsorption. Furthermore, when the concentration of MPEC-IMI is 300 mg L^?1, the corrosion inhibition efficiency can reach up to 92.00%. In support of further study of the corrosion inhibition behavior by virtue of quantum chemical calculation and molecular dynamics simulations, the results show that the MPEC-IMI molecule has high reactivity and strong interaction on the iron surface.     

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.     

酸性介质中羧甲基纤维素钠在低碳钢表面的吸附和缓蚀作用

The effect of sodiumcarboxymethyl cellulose (Na-CMC) on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl solution has been investigated by using weight loss (WL) measurement, potentiodynamic polarization, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) methods. These results showed that the inhibition efficiency of Na-CMC increased with increasing the inhibitor concentration. Potentiodynamic polarization studies revealed that the Na-CMC was a mixed type inhibitor in 1.0 mol·L-1 HCl. The adsorption of the inhibitor on mild steel surface has been found to obey the Langmuir isotherm. The effect of temperature on the corrosion behavior of mild steel in 1.0 mol·L -1 HCl with addition of 0.04% of Na-CMC has been studied in the temperature range of 298-328 K. The associated apparent activation energy (E*a) of corrosion reaction has been determined. Scanning electron microscopy (SEM) has been applied to investigate the surface morphology of mild steel in the absence and presence of the inhibitor molecules.     

红茶提取液在盐酸中对碳钢的缓蚀作用

采用动电位极化曲线和交流阻抗（EIS）研究了红茶提取液（BLE）在盐酸介质中对碳钢的缓蚀性能和缓蚀机理。 研究结果表明,采用索氏提取法从红茶茶叶中提取的缓蚀剂,对碳钢在1.0 mol/L盐酸溶液中具有良好的缓蚀性能,随着提取物浓度的增加,缓蚀效率增大。 红茶提取液中的有效缓蚀成分为抑制阴阳极反应的混合型缓蚀剂,在碳钢表面的吸附符合Langmuir等温式,属于单分子层吸附。     

Study on the Inhibition of Mild Steel Corrosion by Cationic Gemini Surfactant in 1 M HCl

The cationic gemini surfactant 1,2-bis(N-tetradecyl-N,N-dimethylammonium)ethane dibromide (14-2-14) was synthesized using a previously described method. The surfactant was characterized using ¹H NMR. The corrosion inhibition effect of 14-2-14 on mild steel in 1 M HCl at temperatures 30–60°C was studied using weight loss measurements, potentiodynamic polarization measurements and electrochemical impedance spectroscopy. Morphology of the corroded mild steel specimens was examined using scanning electron microscopy (SEM). The results of the studies show that gemini surfactant is an efficient inhibitor for mild steel corrosion in 1 M HCl; the maximum inhibition efficiency (IE) of 98.06% is observed at surfactant concentration of 100 ppm at 60°C. The %IE increases with the increasing inhibitor concentration and temperature. The adsorption of inhibitor on the mild steel surface obeys Langmuir adsorption isotherm. SEM studies confirmed smoother surface for inhibited mild steel specimen.     

Corrosion inhibition investigations of 3-acetylpyridine semicarbazone on carbon steel in hydrochloric acid medium

The corrosion inhibition efficiency of 3-acetylpyridine-semicarbazide (3APSC) on carbon steel (CS) in 1.0 M HCl solution has been investigated using weight loss measurements, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies. The results show that inhibition efficiency on metal increases with the inhibitor concentration. 3APSC exhibited marked inhibition towards carbon steel in HCl medium even at low concentrations. The adsorption of inhibitor on the surfaces of the corroding metal obeys the Langmiur isotherm and thermodynamic parameters (K _ads, ?G _ads ⁰ ) were calculated. Activation parameters of the corrosion process (E _a, ?H* and ?S*) were also calculated from the corrosion rates. Polarization studies revealed that 3APSC act as a mixed-type inhibitor. Surface analysis of the metal specimens was performed by scanning electron microscopy.     

Polyvinyl alcohol–sulphanilic acid water soluble composite as corrosion inhibitor for mild steel in hydrochloric acid medium

The inhibitive action of synthesised polyvinyl alcohol–sulphanilic acid (PVASA) composite on the corrosion of commercial mild steel in 1 M HCl medium has been investigated by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopic (EIS) methods. Characterization of PVASA composite has been carried out using Fourier transform infrared spectroscopy (FTIR). Experimental results reveal that PVASA composite acts as an inhibitor in the acid environment. The inhibition efficiency increases with an increase in the concentration of the inhibitor. Maximum inhibition efficiency of PVASA composite was found to be 84% at 6000 ppm. Thermodynamic and kinetic parameters have been obtained from temperature studies. Electrochemical measurement reveals that PVASA composite acts as a mixed inhibitor and the adsorption follows Langmuir adsorption isotherm.     

Nonionic Surfactants from Recycled Poly(ethylene terephthalate) as Corrosion Inhibitors of Steel in 1 M HCl

Recycled poly(ethylene terephthalate) (PET) can be modified to produce nonionic surfactants. Recycling of PET waste was carried out in presence of triethanolamine and manganese acetate as catalyst. The produced oligomers were reacted with stearic acid and polyethylene glycol, PEG, which have different molecular weights 400, 1,000, and 4,000. The inhibition of corrosion of steel in 1 molar hydrochloric acid solution in the presence of the prepared surfactants is studied by weight loss and electrochemical polarization measurements. The polarization curves indicate that these compounds act as mixed‐type inhibitors. The inhibition efficiency increases with the increase of inhibitor concentration to reach their critical micelle concentrations. The temperature effect on the corrosion behavior of steel in 1 M HCl with and without surfactants is studied in the temperature range from 308 to 343 K. The adsorption of inhibitors on the steel surface is found to increase with increasing the temperature. From the adsorption isotherm, some thermodynamic data for the adsorption process are calculated and discussed.     

Monte Carlo simulation and electrochemical performance corrosion inhibition whid benzimidazole derivative for XC48 steel in 0.5 M H2SO4 and 1.0 M HCl solutions

The inhibition of 1-(4-methoxybenzyl)-2-(4-methoxyphenyl)-1H-benzimidazole (MMB) on corrosion of XC48 steel in solutions 1.0 M HCl and 0.5 M H₂SO₄ were studied by potentiodynamic polarization and electrochemical impedance spectroscopy techniques (EIS). Potentiodynmic polarization curves revealed that MMB acts as a mixed-type inhibitor in both acidic media. The impedance results indicated that the corrosion process occurs under activation control. Furthermore, MMB shows a higher inhibition efficiency in HCl (97%) than in H₂SO₄ (92%) at 10^?4 M MMB. The values of ΔG°_ads, ΔH_a, E_a and ΔS_a in temperature range 293–323 K indicated that MMB strongly retarded the corrosion of XC48 steel in both solutions by a chemisorptions process. The adsorption of Benzimidazole (MMB) on carbon steel surface followed Langmuir adsorption isotherm. Scanning electron microscopy (SEM) analysis confirmed that there is an adsorbed film on the surface of XC48 steel. The results of Monte Carlo simulations studies confirmed the inhibition action of MMB.     

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.     

Schiff’s base derived from the pharmaceutical drug Dapsone (DS) as a new and effective corrosion inhibitor for mild steel in hydrochloric acid

The inhibition ability of Dapsone’s Schiff’s base with salicylaldehyde (1:2) for mild steel corrosion in 1 M HCl solution at 308 K was studied by means of potentiodynamic polarization, electrochemical impedance spectroscopy techniques, and gravimetric analysis. Results showed that Dapsone salicylaldehyde performed well as a good inhibitor for mild steel in 1 M HCl solution with maximum inhibition efficiency of 95 % at 500 ppm. The adsorption isotherm of the inhibitor followed the Langmuir adsorption. The value of free energy of adsorption showed that it is a spontaneous process and followed typical physical adsorption.     

氯化硝基四氮唑蓝对钢在盐酸溶液中的缓蚀作用

采用失重法、动电位极化曲线、电化学阻抗谱(EIS)和扫描电子显微镜(SEM)研究了氯化硝基四氮唑蓝(NTBC)在1.0-5.0mo·lL-1HCl溶液中对冷轧钢(CRS)的缓蚀作用.结果表明:NTBC在1.0mo·lL-1HCl溶液中对冷轧钢具有良好的缓蚀作用,且在钢表面的吸附符合Langmuir吸附等温式.缓蚀率随缓蚀剂浓度的增加而增大,但随盐酸浓度和温度的增加而减小.求出了相应的吸附热力学(吸附自由能ΔG0,吸附焓ΔH0,吸附熵ΔS0)和腐蚀动力学参数(腐蚀速率常数k,动力学常数B),并根据这些参数讨论了缓蚀作用机理.动电位极化曲线表明:NTBC为混合抑制型缓蚀剂;EIS谱在高频区呈容抗弧,在低频区出现感抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大.SEM再次表明NTBC对钢在盐酸介质中的腐蚀产生了明显的抑制作用.