电化学噪声技术检测核电环境材料的腐蚀损伤

探讨和解决了电化学噪声技术在核电环境材料腐蚀损伤检测应用的关键问题,建立了基于零阻电流(ZRA)检测的SCC电化学噪声测试体系.采用小面积的Pt或表面热喷涂陶瓷涂层的工作电极材料作为对电极,研制适用于核电现场检测的多种电化学传感器.运用Compact RIO模块化仪器和设计制作的基于ZRA电路的电化学噪声测试模块,实现电位-电流噪声的同步测量和采集.成功研制出便携式核电材料损伤检测系统.应用研制的测试系统和电化学传感器研究了高温高压和动态水环境304不锈钢的电化学噪声谱特征.并初步实现了在役核电站辅助车间不锈钢管道表面直接腐蚀检测和钢厂动力锅炉连续排污管的现场腐蚀检侧,取得了比较满意的结果.     

钢筋混凝土腐蚀监测技术及其应用

混凝土中的钢筋腐蚀是影响混凝土结构耐久性的主要因素.对钢筋腐蚀进行监测,是钢筋混凝土安全服役的重要保障手段之一.叙述了钢筋腐蚀监测几种常用的电化学测量和物理方法测量技术.分析了各种方法的原理及特点,介绍了各种方法技术在钢筋混凝土腐蚀监测上的应用.并对今后的发展趋势进行了展望.     

耐热钢12CrlMoV在NaHCO3溶液中早期腐蚀行为的电化学噪声研究

运用电化学手段测试和分析耐热钢12CrlMoV在含不同浓度Cl-的0.5mol/L NaHCO3溶液体系中的早期腐蚀行为.电化学噪声测量技术记录12Crl MoV在不同介质条件下早期腐蚀过程的噪声图谱,通过腐蚀形貌观察和极化曲线、微观分析等手段验证电化学噪声分析结果.结果显示,12Crl MoV基体与HCO3-反应形成...     

电化学噪声的分析方法

以电化学噪声测试技术在腐蚀领域中的应用为背景,回顾了近10年来电化学噪声在腐蚀监测、理论研究、图谱分析与数据解析方面的进展,通过了解和掌握电化学噪声测试技术,能从更多的途径知道腐蚀的本质,因而着重阐述了基于时域和频域的分析方法及各自的局限性,最后简介了小波分析的特点。     

微区电化学测量技术在金属电偶腐蚀中的应用

微区电化学测量技术可在微米级甚至亚微米级尺度对金属电偶腐蚀进行原位检测，为深入研究金属电偶腐蚀提供了新途径。介绍了金属电偶腐蚀的基本原理及其主要影响因素，综述了丝束电极技术(WBE)、局部电化学阻抗谱技术(LEIS)、扫描振动电极技术(SVET)、扫描电化学显微技术(SECM)、扫描开尔文探针技术(SKP)等常用的微区电化学测量技术的优缺点及应用现状，最后对其未来发展进行了展望。     

有机涂层性能电化学测试技术的应用进展

综述了电化学测试技术在有机涂层寿命评估、腐蚀过程研究中的进展及应用;分别介绍了电化学阻抗谱(EIS)、局部阻抗谱(LEIS)、电化学噪声(EN)、扫描振动电极(SVET)、扫描电化学显微镜(SECM)、扫描开尔文探针(SKP)等测量技术在有机涂层防护领域的应用;指出了以上方法均有其优缺点,应相互结合、相互验证,并与扫描电镜联合使用,以确保其准确性.     

SKP和LEIS技术在电化学腐蚀研究中的应用进展

介绍了扫描开尔文探针(SKP)和局部电化学阻抗谱(LEIS)两种先进的微区电化学测量技术的原理和优点以及目前主要的应用领域,综述了两种技术在缝隙腐蚀、点蚀和孔蚀、微生物菌腐蚀以及其他类型腐蚀研究中的应用进展。结果表明,两种测量技术对宏观的电化学测量技术有着很好的补充和完善作用。展望了两种技术的未来发展趋势。     

基于扫描探针的金属/有机涂层电化学检测技术的进展

传统电化学检测技术难以深入研究腐蚀的萌生、发展、转移、抑制等过程,而基于扫描探针的电化学检测技术弥补了这一不足。从工作原理和应用现状,简要概述了4种适用于金属/有机涂层体系腐蚀研究的基于扫描探针、具有高空间分辨率的电化学检测技术,分别为扫描电化学显微镜(SECM)、扫描振动电极技术(SVET)、局部电化学阻抗谱(LEIS)、扫描开尔文探针技术(SKP)。4种电化学检测技术均利用金属/有机涂层体系电化学的不均一性,通过检测电流、电压或者阻抗等信号,从微观上反映该体系腐蚀的全过程。基于扫描探针的电化学检测技术的发展及应用,能够从微观上解释金属/有机涂层体系腐蚀发生、发展过程及机理。     

用电化学方法研究混凝土中钢筋腐蚀行为

采用电化学测试技术，研究了混凝土中和Ｃａ（ＯＨ）２饱和溶液中的钢筋电化学过程，研究指出，钢筋混凝土构筑物的腐蚀是由于钢筋与混凝土形成的腐蚀电池作用而产生的电化学腐蚀，进而讨论了用电化学方法评定混凝土中网筋耐蚀性的可行性。     

微区电化学方法在电偶腐蚀领域的应用

概述了近些年来微区电化学测量技术在电偶腐蚀方面的研究进展,包括丝束电极技术(WBE)、扫描电化学显微镜(SECM)、扫描振动参比电极技术(SVET)、局部电化学交流阻抗谱(LEIS)、扫描开尔文探针(SKP)等微区电化学测量技术的应用状况,并对其未来的发展及应用进行了论述。     

Corrosion monitoring of steel in concrete by galvanostatic pulse technique

Various non-destructive quantitative techniques based on electrochemical methods for measuring the corrosion rate of steel embedded in concrete have been used. The most important is the linear polarization method. In practice, this method gives lower corrosion rates of steel in concrete due to inclusion of the resistance of the concrete in the measurement. In order to eliminate the resistance of the concrete, a galvanostatic pulse method is used. In this method the current pulse is applied to the steel in concrete and the polarizing potential is sampled after the switching off the pulse. The performance of the galvanostatic pulse technique for monitoring the corrosion of steel in concrete has been assessed by comparing the corrosion rate values obtained by the weight loss method and linear polarization resistance method for steel reinforced in M15, M20, M30 and M35 grade concrete containing 0–5% NaCl. It is found that the galvanostatic pulse technique is able to give reliable corrosion rate values of steel in concrete.     

Cathodic protection revisited: Impact on structural morphology sheds new light on its efficiency

Cathodic protection (CP) has been found as one of the most viable techniques for inhibiting chloride induced corrosion of steel in concrete structures. This contribution specifically pursues exploring the morphological alterations of corrosion products in reinforced mortars under cathodic protection. For this purpose, scanning electron microscopy (SEM) techniques are combined with energy dispersive X-ray analysis (EDXA) and X-ray diffraction (XRD) for microstructural analysis and quantification of the corrosion products. The combined characterisation provides important insight into the structural alterations induced by cathodic protection, and therefore, help to explain the efficiency of CP techniques. Furthermore, electrochemical measurements are employed to monitor the electrochemical process at the steel–paste interfaces. The beneficial microstructural alterations result in better corrosion resistance of the protected specimens, and turn out to be the mechanisms underlying the efficiency of CP techniques.     

Corrosion Behaviour and Chloride Attack of Reinforcing Steel in Presence of Concrete Admixtures

Corrosion and electrochemical behaviour of reinforcing steel embedded in cement pastes with and without concrete admixtures used in Egypt to modify concrete properties have been studied. The influence of the admixtures on the corrosion resistance of the steel against chloride attack has been studied using impressed current and impressed voltage techniques. The results indicate that the type and concentration of the admixture used have an important effed on the extent of chloride induced corrosion of the steel. The mechanism of corrosion of steel due to chloride attack is discussed.     

Corrosion Measurements of Reinforcing Steel by Different Electrochemical Techniques

Electrochemical techniques of the corrosion measurements of reinforcing steeI in concrete have been evaluated. These techniques include half-cell potential measurements, impressed voltage method, impressed current method and potentiostatic polarization technique. The results of corrosion behaviour of the steel in both 5%NaCl and 5%MgSO4 show that each electrochemical technique provides some information about the condition of the steel bar or the corrosivity of the environment being evaluated, yet none provides a complete data regarding the corrosion resistance of reinforcing steel in aggressive media     

Corrosion Process and Mechanisms of Corrosion‐Induced Cracks in Reinforced Concrete identified by AE Analysis

Abstract: Concrete structures could suffer from the corrosion of reinforcing steel bars (rebars) because of the penetration of chloride ions. For crack detection and damage evaluation in concrete, acoustic emission (AE) techniques have been extensively applied to concrete and concrete structures. In the corrosion process of reinforced concrete, it is demonstrated that continuous AE monitoring is available to identify the onset of corrosion and the nucleation of concrete cracking because of the expansion of corrosion products. At the latter stage, the expansion of corrosion products generates corrosion‐induced cracks in concrete. The generating mechanisms of these cracks are studied in accelerated corrosion tests of reinforced concrete beams. Kinematics of microcracks are identified by SiGMA (Simplified Green’s functions for Moment tensor Analysis) analysis of AE. It is demonstrated that AE activity at the onset of corrosion and at the nucleation of corrosion‐induced cracks is in remarkable agreement with the phenomenological model of the corrosion process in steel. Then, mechanisms of corrosion‐induced cracks are visually and quantitatively investigated by the SiGMA analysis.     

混凝土设计参数对氯盐环境下钢筋锈蚀的影响研究

研究了混凝土设计参数包括水胶比、胶凝材料组成、保护层厚度和混凝土氯离子含量等对氯盐环境下混凝土中钢筋锈蚀的影响。通过模拟氯盐环境下混凝土中钢筋所处的锈蚀环境,并以一定的方法加速混凝土中钢筋的锈蚀,采用电化学测试手段(钢筋腐蚀电位和钢筋腐蚀电流密度)来评价各设计参数对钢筋锈蚀的影响。结果表明,水胶比越小、保护层厚度越大、混凝土氯离子含量越小、使用矿物掺合料能有效延缓钢筋开始锈蚀时间,并在不同程度上减小钢筋的锈蚀速率。试件在试验一段时间后被破损,将钢筋周围砂浆制样并进行SEM扫描电镜元素分析试验,进一步验证电化学测试方法的准确性及钢筋的锈蚀程度。     

Application of electrochemical techniques in investigation of the role of hydrogen in near-neutral pH stress corrosion cracking of pipelines

It has been acknowledged that hydrogen plays a critical role in near-neutral pH stress corrosion cracking (SCC) of pipelines. However, the accurate mechanism for hydrogen involvement remains unknown. This work reviewed the applications of various electrochemical techniques towards understanding near-neutral pH SCC. The techniques reviewed include electrochemical hydrogen permeation, cyclic voltammetry, electrochemical impedance spectroscopy, electrochemical noise and scanning photo-electrochemical microscopy. The manner by which these techniques allow for the investigation of the hydrogen evolution mechanism, adsorption/desorption and permeation kinetics and hydrogen diffusion and accumulation in steel as well as the interactions between hydrogen, anodic dissolution and stress at crack tip in near-neutral pH environmental condition is described. It is anticipated that the advanced electrochemical measurement techniques provide essential tools to investigate the mechanistic aspects on hydrogen involvement in near-neutral pH stress corrosion cracking in pipelines.     

镁水泥混凝土中钢筋的电化学腐蚀研究

为解决分布在西部盐湖地区出现的煤矿矿区钢材腐蚀问题,结合煤矿矿区实际环境,采用实验、理论分析等方法研究了镁水泥混凝土中钢筋的腐蚀.采用CS350电化学工作站,研究镁水泥混凝土中钢筋的电化学腐蚀,结合SEM微观实验和EDS元素扫描结果,对镁水泥混凝土中裸露钢筋腐蚀状况进行描述.研究表明:美加力涂层钢筋状态良好,未出现腐蚀状态;锌美特涂层钢筋出现了低腐蚀现象;而裸露钢筋表面出现了严重腐蚀.钢筋涂层防腐蚀性美加力涂层较好,锌美特涂层次之;涂层钢筋虽然防腐效果不同,但对裸露钢筋的防腐蚀性能有明显有利影响.     

厦门翔安海底隧道钢筋腐蚀监测技术

海底隧道由于其特殊及地质环境的复杂性,为保证海底隧道钢筋混凝土的耐久性与结构服役能力,对其腐蚀状态进行监测尤为迫切。该文研究了翔安隧道钢筋腐蚀监测系统的设计,包括商用的以及基于电化学和物理方法的自主研发的腐蚀传感器,腐蚀监测断面与测点的布置、腐蚀传感器的安装,以及腐蚀数据库的建立。通过现场采集的腐蚀监测数据,评价了翔安海底隧道目前的腐蚀状况。最后介绍了基于超声导波的钢筋腐蚀监测研究新进展。     

吗啉多元胺对混凝土钢筋的阻锈作用

迁移性阻锈剂对钢筋混凝土中的金属材料有很好的保护作用,国内这方面的研究报道较少.采用动电位极化曲线和电化学阻抗谱研究了吗啉多元胺在模拟混凝土空隙液及混凝土中对钢筋的保护作用.在含有2 000mg/L NaCl的模拟液中,吗啉多元胺可以提高钢筋的抗点蚀能力.吗啉多元胺的加入导致混凝土钢筋的腐蚀电位正移,对钢筋的阴极和阳极电化学过程均有抑制作用,它是一种混合型缓蚀剂.吗啉多元胺能够在混凝土中扩散迁移,在钢筋表面形成吸附膜,阻挡侵蚀性离子对钢筋表面的侵入,抑制钢筋腐蚀电化学反应的进行.