甲基丙烯酸二甲氨基乙酯类离子液体 对Q235钢的缓蚀性能

以甲基丙烯酸二甲氨基乙酯为母体、 对氯甲基苯乙烯为季铵化试剂, 合成了一种具有疏水结构的甲基丙烯酸二甲氨基乙酯型离子液体(DEMA). 通过失重实验、 电化学分析、 原子力显微镜(AFM)、 接触角测试和量子化学计算等研究了DEMA在1 mol/L盐酸中对Q235钢的缓蚀性能, 并揭示了其在Q235钢表面的吸附行为和吸附机理. 失重实验结果表明, DEMA在盐酸中对Q235钢具有优异的缓蚀效果, 且在较高温度(60 ℃)下也能保持高效吸附; 电化学实验结果与失重测试结果一致; 接触角测试结果表明, DEMA可明显增强Q235钢表面的疏水性; 分析热力学参数可知, DEMA在Q235钢表面的吸附为自发、 放热过程, 符合Langmuir等温式, 且以化学吸附为主; 量子化学计算结果证实DEMA的结构中包含大量吸附活性位点.     

喹啉型双子季铵盐缓蚀剂的实验及理论分析

以喹啉为母体、 1,4-对二氯苄和顺-1,4-二氯-2-丁烯为联结基, 制备了2种具有疏水结构的水溶性双喹啉季铵盐(BQA-1和BQA-2). 通过失重实验、 电化学测试、 扫描电子显微镜(SEM)及量子化学计算等手段研究了BQA-1和BQA-2对1 mol/L盐酸中Q235钢的缓蚀性能, 并讨论了其在Q235钢表面的吸附机理. 失重结果显示, BQA-1和BQA-2对盐酸中的钢片均具有良好的缓蚀效果, 30 ℃下, 当浓度为0.5 g/L时, BQA-1和BQA-2的缓蚀率均超过94.59%; 升温导致BQA-2的脱附速率比BQA-1更快. 电化学测试结果显示, BQA-1和BQA-2是以抑制阴极为主的混合型缓蚀剂. 分析热力学参数可知, BQA-1和BQA-2在钢表面的吸附为自发、 放热过程, 符合Langmuir等温式, 且以化学吸附为主. 量子化学计算结果表明, BQA-1和BQA-2的吸附活性集中在喹啉环及杂原子上, 且BQA-1和BQA-2分子得电子与Fe作用的能力要强于供电子与Fe作用的能力.     

十八胺基分子组装体在碳钢表面的作用机理与模拟

应用分子动力学模拟明确了以β-环糊精(β-CyD)为主体、 十八胺(ODA)为客体的分子组装体(CDDA)的最优空间构型, 并采用动态失重、 电化学极化与阻抗测试结合扫描电子显微镜、 原子力显微镜、 接触角、 X射线光电子能谱(XPS)与衰减全反射红外光谱(ATR-FTIR)等表面分析手段, 研究了CDDA对Q235碳钢在蒸汽凝结水中的缓蚀机理. 结果显示, CDDA的4种构型可共存于组装体系内; 35 ℃下, 添加1 mmol/L CDDA对碳钢的缓蚀率达94.1%; 添加CDDA不改变腐蚀机理, 但可同时抑制电化学反应的阴、 阳极过程, 并显著提升极化阻抗, 属于阳极抑制为主的混合型缓蚀剂. XPS和ATR-FTIR结果均表明, CDDA在碳钢/溶液界面释放客体ODA, 并由其自发吸附组装形成疏水膜, 吸附过程符合Langmuir等温式. 分子动力学模拟与量子化学计算结果支持上述ODA释放并于金属表面组装成膜的推断.     

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.     

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。     

碱性溶液中苯甲酸抗坏血酸酯对钢筋的缓蚀行为

合成了一种苯甲酸抗坏血酸酯(AB), 利用腐蚀电化学和表面分析技术, 在含3.5% NaCl的饱和Ca(OH)₂溶液中研究了化合物对钢筋的缓蚀性能, 结合量化计算和分子动力学模拟对其在铁表面的吸附行为和缓蚀作用机理进行了分析讨论. 结果表明, AB的添加可有效降低钢筋的腐蚀电流密度, 提高钢筋的耐蚀性能, 表明缓蚀剂对Cl^－引起的钢筋腐蚀具有良好的抑制作用, 为阴极型缓蚀剂. 化合物通过吸附和与铁离子形成不溶性络合物, 可在钢筋表面形成一层保护膜, 进而阻碍介质中Cl^－与金属表面的接触, 且吸附符合Langmuir等温吸附规律. 量化计算和分子模拟结果证明, 分子中内酯五元环和苯环既是亲核反应活性中心, 也是亲电反应中心, 化合物通过与铁原子间的共价键合而以平行于铁表面的方式吸附在金属表面.     

Inhibition of Mild Steel Corrosion in 1 M Hydrochloric Acid Using (E)-(4-(4-methoxybenzylideneamino)-4H-1,2,4-triazole-3,5-diyl) Dimethanol (MBATD)

The inhibition of mild steel corrosion in 1 M HCl by (E)-(4-(4-methoxybenzylideneamino)-4H-1, 2,4-triazole-3,5-diyl) dimethanol (MBATD) was investigated by polarization, AC impedance, thermodynamic, molecular dynamics, and quantum chemical studies. Polarization studies revealed that MBATD act as mixed type inhibitor. Adsorption followed the Langmuir mode with a negative value of free energy, which indicates a stable and spontaneous inhibition process. To understand the energy changes associated with various thermodynamic and kinetic processes, different calculations were made. The correlation between inhibitive action and molecular structure is ascertained through quantum chemical calculations. The adsorption behavior of the inhibitor molecule on mild steel surface has been theoretically computed using molecular dynamics and density functional theory.     

胡麻籽油咪唑啉类缓蚀剂的制备及其缓蚀性能

以胡麻籽油、羟乙基乙二胺为原料合成咪唑啉中间体,用苄基氯进行改性,得到阳离子咪唑啉衍生物。利用FT IR对合成产物进行了表征,用静态失重法、电化学极化曲线和FESEM对其缓蚀性能进行了评价,并考察了不同缓蚀剂浓度、腐蚀浸泡时间对缓蚀效果的影响,探讨了其在A30钢表面的吸附行为。结果表明,合成的缓蚀剂在盐酸体系中对A30钢有较好的缓蚀性能,在浓度为100mg/L时对低碳钢的缓蚀效率可达87%,并且其产物为阳离子型缓蚀剂,吸附满足Langmuir等温吸附方程。最后采用量子化学方法对其缓蚀剂的缓蚀机理进行了分析。     

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.     

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.     

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.     

The effect of some triazole derivatives as inhibitors for the corrosion of mild steel in 5 % hydrochloric acid

Corrosion inhibition by triazole derivatives (n-MMT) on mild steel in 5 % hydrochloric acid (HCl) solutions has been investigated by weight loss and electrochemical methods. The results obtained revealed that these compounds performed excellently as corrosion inhibitors for mild steel in HCl solution. Potentiodynamic polarization studies showed that they suppressed both the anodic and cathodic processes and inhibited the corrosion of mild steel by blocking the active site of the metal. The effect of temperature on the corrosion behavior of mild steel in 5 % HCl with the addition of different concentrations of the inhibitors was studied in the temperature range from 303 to 333 K. The associated activation corrosion and free adsorption energies were determined. The adsorption of these compounds on the mild steel surface obeys the Langmuir adsorption isotherm. The effect of molecular structure on the inhibition efficiency has been investigated by quantum chemical calculations. The electronic properties of inhibitors were calculated and are discussed.     

New anti-corrosion inhibitor (3ar,6ar)-3a,6a-di-p-tolyltetrahydroimidazo[4,5-d]imidazole-2,5(1 h,3h)-dithione for carbon steel in 1 M HCl medium: gravimetric,electrochemical, surface and quantum chemical analyses

The inhibition of (3ar,6ar)-3a,6a-di-p-tolyltetrahydroimidazo[4,5-d]imidazole-2,5(1 h,3h)-dithione (TTHIIDT) for carbon steel was full characterized in a 1 M hydrochloride acid environment at various inhibitor concentrations and temperatures by the gravimetric, electrochemical, surface and quantum chemical analyses. The obtained results confirmed that the inhibition efficiency of TTHIIDT was over 95–97% and nearly stable in the rise of temperature and concentration; TTHIIDT was mixed type inhibitor and effectively influenced both anodic and cathodic corrosion reactions; a protective hydrophobic thin layer of this inhibitor on the carbon steel surface is more stable and non soluble in 1 M HCl medium; this inhibitor adsorbed endothermically on the carbon steel surface by the chemical and physical adsorption processes. The quantum chemical calculations supported the experimental results and showed that the inhibition efficiency is depends on the structure of inhibitor.     

山梨酸钾与Zn2+在NaCl溶液中对Q235钢的缓蚀协同作用

采用失重法、电化学法、X射线光电子能谱(XPS)和扫描电子显微镜(SEM)研究了0.5 mol/L NaCl溶液中,山梨酸钾(PS)与Zn²⁺对Q235钢的缓蚀协同效应。 失重实验结果表明,在0.5 mol/L NaCl溶液中,PS对Q235钢具有一定的缓蚀效果,缓蚀效率随PS质量浓度的增加而增大,当添加PS的质量浓度为25.0 g/L时,最大缓蚀效率仅为38.37%,而PS与Zn²⁺复配后存在显著的缓蚀协同作用,缓蚀效率高达91.03%。 动电势极化结果表明,PS与Zn²⁺混合物可同时抑制Q235钢的阴、阳极反应,属于阳极型缓蚀剂。 阻抗谱表明,该混合物可在电极表面形成致密的保护膜。 XPS分析证明保护膜是由PS、铁的氧化物/氢氧化物和Zn(OH)₂沉淀组成。     

Incorporation of Reactive Corrosion Inhibitor in Waterborne Acrylic Polyurethane Coatings and Evaluation of its Corrosion Performance

Hydroxyl-epoxy phosphate (HEP) as a reactive corrosion inhibitor was innovatively synthesized by the reaction of bisphenol A epoxy resin with phosphoric acid. HEP was mixed with hydroxyl acrylate resin, and crosslinked with waterborne isocyanate curing agent, which was used to form waterborne HEP/acrylic polyurethane composite (HEP-APU) coatings on Q235 steel surfaces. Electrochemical impedance spectroscopy and polarization curves were applied to analyze the corrosion behavior of the HEP-APU coatings in 3.5wt% NaCl solutions. The results indicated that the HEP-APU coatings show a superior passivation property and efficient corrosion protection of Q235 steel. The waterborne acrylic polyurethane coating containing 0.5wt% HEP exhibited the best corrosion performance among all the coating specimens. The improved flash-rust resistance can be attributed to the introduction of the phosphate group which could form phosphate film on the steel substrate.     

Theoretical approach to the corrosion inhibition efficiency of some quinoxaline derivatives of steel in acid media using the DFT method

Corrosion inhibition efficiencies of 1,4-dihydroquinoxaline-2,3-dione (Q1) and 2-phenylthieno[2,3-b]quinoxaline (Q2) as corrosion inhibitors against the corrosion of steel surface in hydrochloric acid is studied by means of density functional approach B3LYP/6-31G calculations. Quantum chemical parameters such as highest occupied molecular orbital energy (E _HOMO), lowest unoccupied molecular orbital energy (E _LUMO), energy gap (ΔE), dipole moment (μ), electronegativity (χ), electron affinity (A), global hardness (η), softness (σ), ionization potential (I), the fraction of electrons transferred (?N), the global electrophilicity ω, and the total energy were calculated. All calculations have been performed by considering density functional theory using the GAUSSIAN03W suite of programs.     

SDBS与HA缓蚀剂复配的实验与理论研究

通过静态失重法研究了十二烷基苯磺酸钠(SDBS)与六亚甲基四胺(HA)在盐酸溶液中对Q235钢的协同缓蚀效应, 并采用分子动力学模拟从缓蚀剂膜抑制腐蚀粒子扩散的角度对其缓蚀机理进行分析. 结果显示: SDBS和HA单独使用时, 最高缓蚀效率分别为82.82%和79.46%, 复配后最高缓蚀效率可达到92.78%; 与两种缓蚀剂单独使用时相比, SDBS与HA复配后缓蚀剂膜体系中的自由空间明显下降, 削弱了膜内缓蚀剂分子的自扩散能力, 腐蚀粒子在缓蚀剂膜携带下的被动迁移也随之减弱; SDBS与HA复配能更有效抑制腐蚀粒子在缓蚀剂膜中的扩散, 也就是说复配后的缓蚀剂具有更好的缓蚀性能.     

盐酸介质中水杨醛缩氨基硫脲对碳钢的缓蚀作用

合成了新型席夫碱缓蚀剂:水杨醛缩氨基硫脲(ST),并考察了其在1 mol/L盐酸溶液中对碳钢的缓蚀性能。通过静态失重、动电位极化曲线、交流阻抗等技术手段研究缓蚀剂浓度对腐蚀速率及缓蚀效率的影响,阐明缓蚀作用机理。结果表明,ST在盐酸介质中对碳钢具有良好的缓蚀性能。随着缓蚀剂浓度的增加,缓蚀效率逐渐增大。ST的加入显著降低了自腐蚀电流密度,为抑制阴极反应为主的缓蚀剂。ST在碳钢表面的吸附符合Langmuir吸附模型,为物理吸附与化学吸附共同作用。     

Q235钢在假单胞菌和铁细菌混合作用下的腐蚀行为

采用腐蚀失重法、电化学阻抗谱(EIS)和表面分析技术研究了Q235钢在假单胞菌和铁细菌共同作用下的腐蚀行为.结果表明:与单种菌相比,两种菌混合作用下Q235钢腐蚀受到了抑制.混菌体系中金属电极自腐蚀电位升高,腐蚀电流密度减小,交流阻抗值随时间增大.扫描电子显微镜(SEM)分析结果表明混合菌体系中Q235钢表面形成了均匀致密的腐蚀产物膜.