模拟深海压力环境下有机涂料/基底金属腐蚀电化学行为研究Ⅰ.海水压力对水在涂层中传输行为和涂层防护性能的影响

于实验室模拟深海压力环境,应用电化学阻抗谱(EIS)研究了有机涂料/基底金属的腐蚀电化学行为.分析海水压力对水在涂层中传输行为和涂层防护性能的影响.结果表明,与常压海水相比,在高压海水(3.5MPa)条件下,该涂层具有不同的电化学阻抗特征,主要表现在高压海水加快了涂层的吸水过程,增大了涂层的吸水率,从而加速了涂层的腐蚀失效过程,致使防护性能变差.     

扫描电化学显微镜在我国金属腐蚀和防护领域的研究进展

金属腐蚀是一种典型的界面电化学反应过程,在金属腐蚀过程中形成的阳极和阴极活性区会导致金属和溶液界面微区的离子浓度发生变化,进而影响金属腐蚀过程的进行.扫描电化学显微镜(scanning electrochemical microscopy, SECM)作为一种扫描探针技术,不但能够表征金属微区腐蚀的物理形貌变化,而且可以记录样品微区的电化学腐蚀过程并探究腐蚀机理,因此在金属腐蚀与防护领域起着重要作用.本综述从回顾我国资深科学家在SECM技术引入中国后所做的与金属腐蚀与防护相关的初始性科学研究入手,首先简要描述了SECM的组成和在金属腐蚀与防护研究领域所应用到的工作模式,进而系统总结评述了我国科研人员近5年利用SECM在金属腐蚀与防护研究方面所作的贡献,最后对SECM在金属腐蚀与防护研究领域面临的挑战进行展望.     

让铁器文物与历史说话*——“金属的电化学腐蚀与防护”教学

以铁器文物的防护为背景,在“金属的电化学腐蚀与防护”主题中,尝试将铁器文物与中学化学教学相结合,通过对不同环境中铁器文物腐蚀原理的探究,了解运用化学原理解释铁器文物保护的方法,使学生掌握金属的电化学腐蚀与防护知识,感受化学对人类的影响,促进学生化学学科核心素养的发展。     

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。     

“钢铁电化学腐蚀原理的再认识”项目式教学

以"钢铁电化学腐蚀原理的再认识"为项目，教师用"项目式教学"的方式引导学生深入地认识钢铁电化学腐蚀原理。详细介绍了教师如何确立项目，如何规划项目，如何实施项目。学生在原有金属腐蚀原理的基础上，又学习了氧浓差电池腐蚀，对原电池的原理有了更加深入的理解。根据氧浓差电池腐蚀的特点，学生提炼了一个合理的简易判据来判断氧浓差电池腐蚀。项目结束之后，学生利用思维导图重新构建了金属腐蚀和防护的知识结构。     

锈层下碳钢和耐候钢的微区和宏观腐蚀电化学行为

采用扫描电化学显微镜(SECM), 辅以极化曲线和电化学阻抗谱(EIS), 并结合SEM和XRD研究了耐候钢和碳钢在干湿交替环境下的腐蚀行为, 包括微区阳极溶解过程和阴极还原行为、 宏观腐蚀过程和微观结构及组成等. SECM测试结果表明, 锈层下碳钢和耐候钢的腐蚀过程都受阳极控制, 锈层的存在促进氧的还原. 宏观和微区电化学测试结果均表明, 在实验周期内, 初期形成的锈层降低了Fe阳极溶解速率, 从而提高碳钢和耐候钢的耐蚀性能, 后期形成的锈层由于其组成和结构特征的变化, 2种钢的腐蚀速率增加; 同时耐候钢的腐蚀速率较碳钢大, 且氧还原也较碳钢强, 有利于锈层的形成, 从而有利于长期的防护, 但是耐候钢的锈层在短期内并没有很好的保护性. 锈层不够致密, 呈疏松多孔状, 其组成主要有晶态的γ-FeOOH, Fe₃O₄和γ-Fe₂O₃等, 相同的干湿循环条件制备的耐候钢锈层较碳钢厚.     

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。     

中学化学教学中的有关电化学问题：谈原电池,电化学腐蚀

本文讨论了中学电化学教学中的两方面问题：一是电化学中的三大类电极如何构成各种原电池,并正确写出电极反应和电池反应,由反应正确设计出电池提出了规律性建议并示例;二是将原电池理论应用于电化学腐蚀,讨论了析氢腐蚀和吸氧腐蚀的可能性及规律,并解释了中学常见的疑难问题。     

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.     

2006年全国腐蚀电化学及测试方法学术会议

由厦门大学承办的2006年全国腐蚀电化学及测试方法学术会议将于2006年5月中旬在厦门大学、武夷山举行.自第一轮会议通知发出后,得到许多委员和腐蚀电化学专家及同行的热情支持,现按会议筹备工作计划发出第二轮通知,会务组决定编辑会议论文集,优秀论文将推荐给《电化学》期刊发表.欢迎大家按以下格式踊跃投稿.一.会议征文内容1.腐蚀电化学基础研究2.复杂体系的腐蚀电化学研究3.微纳米技术在腐蚀电化学研究中的应用4.腐蚀控制的电化学技术及进展5.腐蚀电化学测试、监测及仪器二.论文及格式要求1.直接提交全文,文责自负.通讯联系人以*于该作者…     

SECM基本原理及其在金属腐蚀中的应用

扫描电化学显微镜（SECM）是一种具有较高空间分辨率的化学显微镜,在成像和动力学研究已经广泛应用. 本文简要介绍SECM基本原理,综述2009年以来SECM在腐蚀方面的应用,包括扫描成像和异相转移电子化学活性的研究,并简要介绍了作者课题组在SECM方面的研究工作,展望SECM在腐蚀研究的应用.     

Synthesize,Characterization, and Corrosion Inhibition of Polypyrrole Thin Films on Copper

Polypyrrole (PPy) coatings were synthesized on copper by electrochemical polymerization of pyrrole monomer in aqueous acidic and basic solutions by cyclic voltammetry. The coatings were characterized with CV, UV-visible absorption spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) techniques. The corrosion protection aspects of PPy coatings have been investigated using the potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements show that the PPy coating has ability to protect the copper against corrosion. It was concluded that a complete corrosion protective PPy film could not be obtained through direct electro-oxidation procedure. This may be due to copper dissolution in the monomer oxidation potential range.     

Electrochemical impedance spectroscopy for characterization of coatings with intrinsically conducting polymers

The method of electrochemical impedance spectroscopy (EIS) was applied to investigate the behaviour of a thin intrinsically conducting polymer film (ICP) deposited on a metal substrate. Especially the conductivity, the redox properties, the anion release properties, and the corrosion protection of a coating with and without ICP film on an iron or steel substrate were studied. Combined with other electrochemical methods, the reactions taking place at an injured surface area of the coated iron were studied. The corrosion protection mechanism of polythiophene could be explained.     

hytic Acid Conversion Coatings of Magnesium

A chrome‐free conversion coating treatment for magnesium by phytic acid solution was developed. The immersion experiments were used for evaluating the effects of the processing parameters (such as conversion temperature and time, concentration and pH value of phytic acid solution) on the corrosion resistance of the phytic acid conversion coating. The morphologies and compositions of the coatings were determined by SEM and EDS respectively. The experimental results indicated that the corrosion resistance of the conversion coating formed in the solution containing 0.5% phytic acid at 25°C and pH=4 for 30 min was higher than that of natural oxide, and the conversion coating formed on the surface of magnesium was of multilayer mainly consisting of Mg, C, O and P. The thicknesses of the conversion coatings were approximately 1.0–15 µm and the conversion coatings presented obvious network‐like cracks. The electrochemical potentiodynamic polarization experiment indicated that the free corrosion potential of the magnesium with phytic acid conversion coating was increased, and its corrosion current and corrosion rate declined in 3.5% NaCl solution. Phytic acid conversion coating could improve the electrochemical property of magnesium and provide effective protection, which can improve the corrosion resistance of magnesium.     

Corrosion behavior of magnesium and its alloy in NaCl solution

The electrochemical behavior of cast Mg, AZ91, and cast AZ91 in 0.1 M NaCl solution is investigated by measuring open-circuit potential (OCP), steady-state current-potential, and electrochemical impedance spectra (EIS). The similar electrochemical impedance behavior is found of three corrosion electrodes. There are two capacitances in high-and medium-frequency domains and one inductive loop or component in low-frequency domain. From equivalent circuit simulation, cast AZ91 has the worst corrosion resistance. The EIS results are in good agreement with those obtained by OCP and polarization curves. Based on the Cao theory, a simple corrosion mechanism is put forward, supplying a possible explanation for low-frequency inductive behavior for Mg and its alloy in NaCl solution at OCP. Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 7, pp. 878–885. The text was submitted by the authors in English.     

Corrosion resistance of amorphous AlPO4 coating in salty atmospheres

The objective of the present study was to introduce a cost-effective and environmentally friendly coating to improve the corrosion resistance of the structures located in salt water. The coating solution, based on amorphous aluminum phosphate composition, was synthesized by sol–gel process and applied to AISI 304 stainless steel by dip coating technique. X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy analyses were employed to investigate the phase composition and morphology of the coating. Corrosion behavior of the uncoated and coated samples was investigated using standard salt spray test, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. Salt spray test results for the bare substrate revealed a corrosion rate of six-time greater than that of the coated surface after 168 hr exposure time. Electrochemical test results declared that the amorphous AlPO₄ coating decreased the corrosion current density of the AISI 304 stainless steel by 10 orders of magnitude. Furthermore, according to the corresponding EIS measurements, the coated surface exhibited a superior anti-corrosion performance than uncoated sample. Overall, the results declared that the amorphous AlPO₄ coating could be a good choice for surface protection of stainless steel against electrochemical corrosion in salty environments.     

A facile method for fabrication of superhydrophobic coating on aluminum alloy

A superhydrophobic coating applied in corrosion protection was successfully fabricated on the surface of aluminum alloy by chemical etching and surface modification. The water contact angle on the surface was measured to be 161.2° ± 1.7° with sliding angle smaller than 8°, and the superhydrophobic coating showed a long service life. The surface structure and composition were then characterized by means of SEM and XPS. The electrochemical measurements showed that the superhydrophobic coating significantly improved the corrosion resistance of aluminum alloy. The superhydrophobic phenomenon of the prepared surface was analyzed with Cassie theory, and it was found that only about 6% of the water surface is in contact with the metal substrate and 94% is in contact with the air cushion. Copyright © 2011 John Wiley & Sons, Ltd.     

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.     

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.     

体外电化学测试对镁合金体内降解行为的预测

可生物降解镁合金因同时具有优良的生物相容性和力学性能,在生物医学界显示出其作为新型骨科内植入物的巨大潜在优势和市场前景。目前,作为制约镁合金医用产业化的关键因素,即过快的降解速率已经成为研究重点。本文回顾了体外电化学测试技术对镁合金抗腐蚀性能的研究,并分析了模拟腐蚀体系对镁合金腐蚀行为的影响;同时评估了电化学测试方法作为快速有效预测镁合金体内降解性能前期分析手段的可行性与局限性。最后,对如何发展更合理的体外电化学测试技术来预测镁合金体内降解提出了可能的解决方法及构思。