两种席夫碱缓蚀剂对碳钢材料的缓蚀性能探究

采用了电化学方法研究了2种席夫碱缓蚀剂水杨醛基邻苯甲酸亚胺(SB-I)和N,N’-二水杨醛基-1,2-邻苯二亚胺(SB-II)在1 mol/L盐酸溶液中对20#碳钢的缓蚀性能。通过极化曲线和交流阻抗谱研究该席夫碱对碳钢的缓蚀效果表明:席夫碱对碳钢材料具有良好的缓蚀作用,其最大缓蚀率可达到83%。研究了席夫碱在碳钢表面的吸附模式,结果表明,席夫碱在碳钢表面上的吸附吉布斯自由能在-30 kJ/mol之间,表现为混合型缓蚀剂,即通过化学吸附和物理吸附之间的一种混合吸附在碳钢工作电极的表面,通过抑制、阻止延缓金属的电化学过程而起到缓蚀的作用。另外,实验还发现,SB-I比SB-II具有更好的缓蚀性能,该实验结果与理论计算结果相符合。     

高效液相色谱法测定防锈纸中苯三唑和苯甲酸(盐)的含量

<正>防锈纸是一种能够防止金属材料发生锈蚀的功能防护用纸。防锈纸有接触型防锈纸和气相防锈纸两种。目前国内外生产和使用得最多的防锈纸是气相防锈纸,气相防锈纸的核心成分为气相缓蚀剂,由于单独使用一种气相缓蚀剂往往不能满足气相防锈纸的某种要求,因此气相缓蚀剂一般采用多种联用的方式来弥补这一不足^[1-5],苯三唑、苯甲酸(盐)是最常用的两种缓蚀剂。苯三唑属于有机杂环化合物,对铜、银、钢、锌、锡等金属均有缓蚀效果,复配使用时具有更高的缓蚀效率,     

噻二唑衍生物对银的缓蚀性能研究

本文研究了主要成分为5-甲基-2-戊基二硫代-1,3,4-噻二唑的复配型缓蚀剂TSJ-T6,在浓度为5.0×10-5g/g的H2S中对银的缓蚀性能。通过增重实验、接触角分析、电化学极化曲线测试以及分子动力学模拟研究了该缓蚀剂的缓蚀效率及缓蚀机理。增重实验结果证明,缓蚀剂TSJ-T6对银片在H2S中的腐蚀具有良好的缓蚀效果,缓蚀剂浓度为2.5×10-5g/g时,缓蚀效率高达94.51%。接触角分析结果表明,该缓蚀剂分子在银片和腐蚀液的界面形成了一层疏水保护膜。极化曲线结果表明,缓蚀剂TSJ-T6的存在降低了阴、阳极的塔菲尔斜率,为混合型缓蚀剂;同时,该缓蚀剂的存在显著降低了腐蚀电流密度,表明该缓蚀剂对银片在H2S中的腐蚀有良好的缓蚀效果。分子动力学模拟表明,缓蚀剂分子通过噻二唑环和链上的硫、氮原子吸附在银表面,烷基链则以一定角度指向溶液。     

纳米材料制备技术在化学综合实验课程中的应用

在应用化学等专业的化学综合实验课程中,开设24学时的综合实验项目＂金属氧化物无机纳米材料的合成、表征和性能研究＂,使学生了解纳米材料的化学制备方法及化学性能检测技术。介绍了该实验的开设背景,教学目的,教学内容及教学效果。     

气相色谱法测定五水硫酸铜的脱水机理

目前,许多学校化学系开设的“配位化学”实验中一般采用了经典的差热—热重法检测配合物热分解过程的实验。气相色谱作为一种常用的分析测试手段,对于非分析专业的学生来说,除了在基础分析化学课程中有所涉及外,很少有动手实践的机会。把气相色谱引入配位化学实验,既可以使学生巩固前面课程所学气相色谱原理及操作方法,同时也使学生了解到色谱法在无机化学领域     

氨基酸缓蚀剂在盐酸溶液中对钢的缓蚀作用

应用极化曲线、电化学阻抗谱等测试技术,研究了以谷氨酸作缓蚀剂在10%盐酸介质中对X65钢的缓蚀作用,测试腐蚀参数包括腐蚀电位(Ecorr)、极化电阻(Rp)、缓蚀效率(η)等.研究表明:该缓蚀剂是一种抑制阴极为主的混合型缓蚀剂,在较低的浓度具有良好缓蚀效果;缓蚀效率随着浓度的增加而提高,并在0.3g.L-1时达到最大值(90%以上).     

2-十一烷基-N-羧甲基-N-羟乙基咪唑啉在柠檬酸溶液中对碳钢的缓蚀作用

采用失重实验、极化曲线和交流阻抗等方法研究了缓蚀剂2-十一烷基-N-羧甲基-N-羟乙基咪唑啉在质量分数为2%柠檬酸溶液中对碳钢的缓蚀性能。 失重实验表明,该缓蚀剂在柠檬酸溶液中能够有效地抑制碳钢的腐蚀,当其质量分数为0.4%时,缓蚀效率达到86.4%。 极化曲线表明,该缓蚀剂为混合型缓蚀剂,Nyquist图中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。 该缓蚀剂的吸附行为符合Langmuir吸附等温式,吸附机理是介于物理吸附和化学吸附之间的一种吸附。     

巯基三唑缓蚀剂构效相关性的灰关联分析

应用灰关联分析方法研究了巯基三唑缓蚀剂缓蚀性能和分子结构参数之间的关系.根据灰关联度的计算,找出影响缓蚀效率的主要分子结构参数.在此基础上将提出的缓蚀效果评价因子用于巯基三唑化合物缓蚀性能的预测,理论预测结果和实验事实相符合.     

气相自由基反应动力学的光电离质谱研究

气相自由基能与各种气体发生快速反应,在大气化学、燃烧化学和星际化学等重要的化学过程中起着关键性的催化作用。许多实验方法(例如荧光法和吸收法)已经用于研究气相自由基反应动力学过程,并取得许多重要的成果,但这些技术局限于探测小分子自由基反应。流动管反应器和闪光光解结合光电离质谱的实验技术以其通用性、多重探测性、选择性和灵敏性等多种优势,成为研究气相自由基反应的主要实验方法。本文介绍利用高通量、高分辨、连续可调的同步辐射光电离质谱开展多种自由基反应研究所取得的一些独创性的成果。另外,该技术具有独有的时间分辨、能量分辨和异构体分辨的能力,能够广泛用于大气化学、燃烧化学和星际化学中一些重要的气相自由基(如烷氧自由基、烃类自由基等)反应宏观动力学过程的研究。     

稀土铈(IV)离子和钼酸钠在盐酸溶液中对冷轧钢的缓蚀协同效应

用失重法和电化学法研究了盐酸介质中,稀土铈(IV)离子和钼酸钠对冷轧钢的缓蚀协同效应.研究结果表明,钼酸钠和稀土Ce⁴⁺对冷轧钢都有一定的缓蚀作用,但最大缓蚀率不超过42%.通过吸附模型的讨论发现,在Langmuir吸附模型的基础上进行校正后的模型能更合理地解释实验结果,并求出了三个吸附参数.通过对比实验,发现稀土铈(IV)离子和钼酸钠对冷轧钢产生了明显的缓蚀协同效应,最大缓蚀率可达90%左右.     

Sources of electrochemical noise in corroding systems

The electrochemical noise method is reasonably well established as a technique that can estimate corrosion rate through the electrochemical noise resistance or impedance. A more interesting potential application is the identification of the nature of the corrosion process. In this paper, a number of corrosion types are examined, and it is concluded that the majority constitute a form of shot noise, possibly with a superimposed baseline current. Methods by which parameters describing the shot noise process can be estimated from the measured data are presented. It appears to be feasible to extract the charge in the shot noise events, and their frequency, providing all of the anodic or cathodic current, is associated with these events. However, the analysis requires a number of assumptions that are not always valid, and these are discussed. Finally, some alternative methods that have been used to identify the type of corrosion are briefly discussed. Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 5, pp. 557–566. The text was submitted by the author in English.     

Influence of inhibitor structure and metal/solution interface on the corrosion resistance of the protected metal

Seven systems of more than 60 compounds with possible inhibiting properties are investigated. Several methods are used: electrochemical, gravimetric, XPS, and SEM analyses. The inhibition efficiency Z is related to the chemical structure of inhibitors (sequences of compounds with regard to Z are found), their electronic structure, the surface area of the inhibiting molecule, and the structure and composition of the metal/solution interface (impedance, adsorption equilibrium parameters, etc.). The most efficient of the investigated inhibitors have Z = 94–99%. Conclusions are drawn which allow identification of compounds with prognosticated inhibiting action. Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 11, pp. 1352–1364. Based on the report delivered at the 8th International Frumkin Symposium “Kinetics of the Electrode Processes,” October 18–22, 2005, Moscow. The text was submitted by the authors in English.     

Analysis of pitting corrosion rate

A method for estimating pitting corrosion rate is proposed. The method is based on the analysis of anodic and cathodic voltammograms that were measured on the specimens of two types: on the test specimen coated with an oxide film, which formed under the open-circuit conditions, and on the specimen, whose surface was totally activated with aggressive ions. The use of Tafel portions of these voltammograms in various combinations enables us to estimate the corrosion potential and corrosion current for general corrosion proceeding in the induction period, for pitting corrosion at the initial stage of its development, for a highly developed pitting corrosion, when the major area of specimen surface is occupied with pits, and also in the intermediate case.     

Characteristics of CO2 corrosion scale formed on P110 steel in simulant solution with saturated CO2

The SEM, X‐ray diffraction (XRD), and XPS were employed to systematically characterize the component and microstructure of the corrosion scale formed on P110 steel exposed to carbon dioxide (CO₂) environment. A loose and porous microstructure in corrosion scale was observed under turbulent flow condition for 120 h at 100 °C with a carbon dioxide partial pressure of 4 MPa in which the principal component was iron carbonate (FeCO₃), whereas at 160 °C the corrosion scale was composed mainly of FeCO₃ and a little amount of FeO(OH). In addition, complex carbonate (Mg,Fe)CO₃ was produced because some Fe positions in FeCO₃ lattice were substituted by Mg. It showed that a double‐layer structure of corrosion scale was observed at 160 °C compared with the result at 100 °C. Copyright © 2008 John Wiley & Sons, Ltd.     

Adsorptive passivation of iron by organic acid anions

Studies on the iron passivation by organic acid anions in aqueous solutions are briefly reviewed. It is shown that the passivation can be caused only by their adsorption, retarding both the iron dissolution and the formation of oxide films. Earlier, it had been believed that oxide films play a dominant role in the iron passivation in neutral solutions. The recent viewpoint is that such nonoxide iron passivation can occur in solutions of salts of not only aromatic amino acids (sodium phenylantranilate and its substitutes), but other carboxylic acids as well. An important role of chemisorption and hydrophobic properties of anions for the formation of adsorption passive films is emphasized. New possibilities for inhibitor protection of iron against corrosion, which is based on adsorptive passivation, are pointed out.Translated from Elektrokhimiya, Vol. 40, No. 12, 2004, pp. 1503–1507.Original Russian Text Copyright © 2004 by Kuznetsov.     

“缓”然一新——深蓝里的金属防腐*

缓蚀剂和缓蚀涂层能够在金属表面形成一层致密保护膜,从而达到延缓金属腐蚀的目的。其具有成本低、可操作性强、缓蚀效果好、寿命长等优点,成为海洋工程防腐中一类重要的材料。围绕海洋工程中钻井平台、风力发电机、航空母舰和核潜艇等中易发生腐蚀的部位介绍化学缓蚀剂及缓蚀涂层的结构、性质,并突出其重要作用。     

The influence of Ce3+ ions on the corrosion rate of stainless steel in acidic solutions of different pH-values

The corrosion resistance of AISI 420 stainless steel in 0.1 mol L^?1 H₂SO₄ + 0.1 mol L^?1 Na₂SO₄ solutions at different pH-values and the inhibiting effect of Ce³⁺ ions was studied using electrochemical polarization methods. The results reveal decreasing of the corrosion rate with an increasing the pH of the solution, which demonstrates the progressive protective character of the inhibitor used. At pH lower than 3.33, the corrosion inhibition was most probably a result of the competitive adsorption of Ce³⁺ with H⁺ ions on the cathodic sites of the electrode surface, and it was found to be dependent on the relative concentration of H⁺/Ce³⁺. The peroxide generated from the oxygen reduction reaction at pH 3.33 was found to be capable oxidize trivalent cerium (Ce) to the tetravalent state. As obtained hydroxide precipitates act as diffusion barrier hindering the corrosion processes, whereafter a spontaneous passivity occurs on the steel surface at this pH.     

Corrosion evolution of UNS C90300 bronze in simulated acid rain of Hong Kong

Corrosion evolutions of UNS C90300 bronzes with and without artificial patina were investigated in the simulated acid rain of Hong Kong. The corrosion products mainly composed of cuprite were formed on the surface exhibiting slight protection for the bronze substrate. The ratios of Sn and Zn in the corrosion products are lower than in the alloy. The artificial patina effectively enhances the corrosion resistance of bronze substrate, even after 30 days of immersion. For both bare and patinated bronzes the Sn- and Zn-based species are absent in the outer layers of corrosion products, and Cu₂O species in the outer layer can partially transform into Cu (II) ionic state due to the abundant supply of dissolved oxygen.     

Pitting on the 20Kh13 steel in chloride solutions

The dependences of the pitting potential, determined by potentiodynamic method, on the NaCl solution concentration, pH, and temperature are found. The repassivation potential and the induction time for the pitting under different conditions are determined. The corrosion potential and kinetic parameters of the steel dissolution in pits are measured. The corrosion current is evaluated, leading to the determination of the steel dissolution rate in pits at the corrosion potential.     

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。