利用手持技术数字化实验探究自热包的电化学腐蚀发热原理

针对电化学腐蚀概念教学存在的不足,以手持技术数字化实验的TQVC概念认知模型为研究思路,定性与定量相结合,设计手持技术数字化实验以促进学生对电化学腐蚀概念的认知。利用温度传感器、氧化还原传感器、pH传感器,测定镁水型自热包在溶液中工作的温度曲线、氧化还原电势曲线、pH曲线,通过多重表征的手段解析镁水型自热包的腐蚀原电池工作原理、腐蚀发热原理、缓释均布剂与包埋剂的作用、各类型饭盒的加热效果,旨在帮助学生从装置-原理二维视角认识电化学腐蚀的本质,以期为日常教学提供参考。     

基于传感器探究酸性条件下铁的吸氧腐蚀

人教版《化学反应原理》中介绍了金属的电化学腐蚀，主要是钢铁的吸氧腐蚀和析氢腐蚀。结合教材分析铁的腐蚀原理，得出铁的析氢腐蚀会导致体系压强增大，吸氧腐蚀会导致体系溶解氧减小。据此利用压强传感器和溶解氧传感器探究酸性条件下铁的吸氧腐蚀，并设计正交实验寻找发生吸氧腐蚀的最佳条件，帮助学生进一步理解铁的吸氧腐蚀。     

pH/Cl-复合探针技术对钢筋混凝土电化学除氯的原位检测

采用恒电流法电化学除氯处理受氯离子污染的钢筋混凝土试样,并用pH/Cl^-复合探针原位检测电化学除氯过程钢筋混凝土不同位置孔隙液的氯离子含量与pH值分布,同时用线性极化曲线和交流阻抗谱图等电化学技术考察钢筋的腐蚀性能,探讨电化学除氯过程的混凝土微环境和钢筋腐蚀速率. 研究结果表明：在电化学除氯过程,混凝土孔隙液的氯离子浓度逐降,而pH值在初期略有升高,随之其pH值略降;电化学除氯施加的阴极电流,使钢筋处于阴极极化状态而得到保护;除氯停止（即退极化）后钢筋的腐蚀电位明显正移,腐蚀电流降低,极化电阻升高,表明电化学除氯能改善钢筋的腐蚀环境,降低钢筋的腐蚀速率.     

空间分辨电化学技术用于研究金属局部腐蚀

综合介绍我们已建立的具有微米空间分辨度的电化学方法,主要包括多种扫描微电极技术,并用于研究金属表面和金属／溶液界面电化学不均一性及局部腐蚀破坏过程。结果表明,这些空间分辨电化学方法的发展及应用,有助于深化对金属表面和金属／溶液界面电化学不均一性,特别是金属局部腐蚀发生、发展过程机理的认识。     

18／8型不锈钢在受力形变条件下腐蚀电化学行为的研究

应用电化学稳态技术、电化交流阻、抗微区电化学技术及扫描电等方法，研究１８／８型不锈钢在Ｎａ２Ｓ２Ｏ３稀溶液中，受外力形变条件下，的腐蚀电化学行为，结果表明，力学因素可使表面腐蚀电化学活性增加，表面微裂纹的发生、消失和再钝化的动态过程，同时受电位和拉应力的影响；点腐蚀可优先发生在应力集中位置，点蚀的发展可能诱导不锈钢的应力腐蚀开裂。     

金属腐蚀与防护简谈

本文简要阐明了为什么金属的腐蚀主要以电化学腐蚀的形式出现,剖析了腐蚀过程电化学动力学参数的物理意义,以及金属腐蚀的防护原理、常用的腐蚀防护方法乃至腐蚀过程的一些特殊应用。     

5083铝合金在海水中的腐蚀电化学行为及活性氯影响研究

采用动电位极化、循环极化和全浸腐蚀试验方法,研究了5083铝合金在静止海水中的腐蚀电化学性能以及活性氯的影响.结果表明,在本文设置的防污活性氯浓度范围(0.2～0.5mg/L)内,活性氯对铝合金的阴极和阳极电化学极化以及腐蚀行为没有明显影响,并可提高铝合金的耐点蚀能力,海水的pH值对铝合金的腐蚀具有显著的影响.该研究为海水中5083铝合金的防腐防污提供了依据.     

AZ31和AZ61镁合金在模拟海水中的腐蚀电化学行为

应用极化曲线、电化学阻抗谱方法研究了两种Mg-Al-Zn系合金——AZ31和AZ61在模拟海水中的腐蚀电化学行为.根据两种镁合金在浸泡过程中腐蚀介质pH值的变化以及扫描电子显微镜对合金微观金相组织和腐蚀形貌的观察,讨论了镁合金的腐蚀机理及合金元素Al的含量对镁合金耐蚀性能的影响.结果表明,AZ61镁合金具有比AZ31镁合金更好的耐蚀性能,其原因主要是AZ61镁合金中Al含量较高使合金的微观组织结构更有利于耐蚀性能的提高.     

化学/电化学腐蚀法快速制备超疏水金属铝

提出一种金属铝超疏水表面的快速制作方法. 先以化学腐蚀在铝表面形成微米级粗糙结构, 再通过电化学腐蚀构筑纳米结构, 在20 min内完成了超疏水表面所需粗糙结构的制备. 这种化学腐蚀/电化学腐蚀两步法比单独化学或电化学腐蚀方法在时间上缩短了1~2个数量级, 且不受铝材晶形限制, 同时电化学腐蚀所用电流密度也降低了1个数量级, 降低了对电源设备的要求, 可望大规模应用于工业生产和其它金属的超疏水表面制备.     

混凝土中钢筋的腐蚀行为研究

本文探讨了在不同 pH和Cl- 含量的模拟混凝土孔隙液介质中 ,混凝土中钢筋的腐蚀电化学行为 .电化学技术测试结果表明 ,正常情况下 ,钢筋在混凝土中受到高碱性环境的保护 ,耐蚀性好 .但随着介质 pH的降低、Cl- 含量的上升 ,钢筋腐蚀电流升高 ;动电位阳极极化曲线的测试表明 ,钢筋的维钝电流增大 ,击穿电位负移 ,混凝土中钢筋的耐蚀性下降 .这是钢筋表面钝性受破坏的缘故 .     

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.     

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.     

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.     

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.     

Corrosion fatigue on 2024T3 and 6056T4 aluminum alloys

Fatigue corrosion phenomenon is a form of degradation that is because of the combined occurrence of a mechanical cyclical stress and a corrosive environment. Fatigue corrosion can be an issue in commercial and military aircraft, and has the potential to affect the structural integrity and the useful life of an aerostructure. Although the distinct consequences of both fatigue and corrosion have been extensively documented for aluminum alloys, their synergistic action is not completely understood and continues to be an area of considerable scientific and industrial interest. In this paper, a novel approach is proposed and applied for monitoring the electrochemical behavior of different types of aluminum alloy samples while they are subjected to fatigue loading. Cyclic load experiments were conducted on bare 2024T3 and 6056T4 aluminum alloy samples in the presence of an aggressive aerated solution of 3.5% NaCl over a range of frequencies. The R‐ratio was 0. Two different aluminum alloys have been tested in both high‐ and low‐cycle fatigue. In the former case, the maximum stress experienced by the specimen is lower than the material yield strength, which means that the average expected number of cycles to failure is high; in the latter case, the maximum stress experienced by the specimen during the test is higher than the material yield strength, which means that the average expected number of cycles to failure is low. The open circuit potential(OCP) was monitored versus time during the tests described above. The observed OCP variations are interpreted as the occurrence of corrosion during crack initiation and propagation at the air formed oxide/solution interface film. As expected, there is a more pronounced influence of corrosion at lower fatigue frequencies. Crack propagation allows bulk material to be progressively more exposed to the aggressive environment, which stimulates accelerated crack propagation, resulting in a lower fatigue resistance. Copyright © 2010 John Wiley & Sons, Ltd.     

RESEARCH ON POWDERY CORROSION OF THE SERIALS BELLS FROM CAI HOU TOMB

"Powdery corrosion" is called "cancer" of cultural relics of bronze. For many years theexperts concerned at home and abroad cannot make distinct progress in the control or cure ofpowdery corrosion. This paper introduces in detail analyses of XRD, SEM. TEM and XRFA on afragment of serials bells with serious powdery corrosion from the Cai Hou Tomb, pointingout that the components of powdery corrosion are mainly atacamite (Cu_2(OH)_3Cl), cuprite(Cu_2O) and cassiterite (SnO_2) in the worse crystalline state. In the bell's matrix, there arecorrosion gullies which has the same phase components as the powdery corrosion. Obviously,this discovery has very important significance for studying the formation mechanism ofpowdery corrosion.     

季铵化聚乙烯亚胺对低碳钢缓蚀性能与机理

采用叔胺化反应与季铵化反应2步高分子反应过程,制备季铵化的聚乙烯亚胺(QPEI),采用静态挂片失重法与电化学极化曲线测定法,研究了在H2S04溶液中QPEI对低碳钢的缓蚀性能与缓蚀机理,并使用扫描电子显微镜对缓蚀样片表面膜层进行了分析. 实验结果表明,QPEI对低碳钢具有优良的缓蚀作用,在0.5 mol/L的H2S04介质中,QPEI的质量浓度仅为5 mg/L,A3钢片的腐蚀时间为72 h时,缓蚀率高达91%;QPEI可同时抑制阴极过程与阳极过程,其缓蚀作用属混合型;在物理吸附与化学吸附的协同下,QPEI在碳钢表面会形成致密的吸附膜,它在钢板表面的吸附行为符合Langmuir单分子层吸附等温式.     

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.