Evaluation of Anticorrosion of NaNO2 on Reinforcing Steel in the Simulated Concrete Solution

Reinforcing steel in concrete is usually in a passive condition due to the high alkalinity of the pore solution contained in the pores of concrete. However, the passivation may be lost and the corrosion occurs on the steel by a deceased of pH due to carbonation and/or by the penetration of chloride ions which come from the corrosion environment at the metal concrete interface. Pitting corrosion caused by the chloride is most harmful. Corrosion inhibitors can be applied to protect steel in the presence of chloride ions. The anticorrosion action of NaNO₂ on the reinforcing steel in the simulated concrete solution containing NaCl has been studied using electrochemical technique and the other methods in this paper.     

LD-2复合缓蚀剂对海水介质混凝土中钢筋阻锈作用研究

利用电化学检测技术和海水浸泡试验等方法 ,观测和研究了经筛选研制的LD_2复合缓蚀剂对海水介质中钢筋腐蚀电化学行为的影响 ,考察和评价了复合缓蚀剂对钢筋的阻锈作用 .结果表明 ,LD_2复合缓蚀剂主要起阳极型缓蚀剂作用 .在海水中加入 2 5 g·L- 1复合缓蚀剂后 ,钢筋的腐蚀电位提高约 0 .2 2 0V ,腐蚀电流降低至未加缓蚀剂的 1% ,缓蚀效率达 99% .钢筋混凝土试样在海水中浸泡 2年 ,表明混凝土中加入占水泥重量 1.0 %～ 2 .5 %LD_2复合缓蚀剂时 ,能有效阻止混凝土中钢筋的腐蚀     

基于癸二酸二异辛酯的环保型复合缓蚀剂对钢筋的缓蚀效应

应用缓蚀剂控制混凝土中钢筋的腐蚀具有高效、廉价和易操作等优点,越来越受腐蚀研究者的关注。近年来,对环保型缓蚀剂的需求日益增加。因此,本工作发展了由癸二酸二异辛酯、D-葡萄糖酸钠和硫酸锌组成的环保型复合缓蚀剂并应用电化学测试技术和表面分析方法研究其对钢筋的缓蚀作用。结果表明,Q235钢筋在pH为11.00,含0.5 mol∙L^-1 NaCl的模拟污染的混凝土孔隙液中处于活化状态并发生局部腐蚀。含有59 mmol∙L^-1癸二酸二异辛酯,0.5 mmol∙L^-1 D-葡萄糖酸钠和1.5 mmol∙L^-1硫酸锌组成的复合缓蚀剂对钢筋具有良好的协同缓蚀效应,在模拟污染混凝土孔隙液中和水泥砂浆试样中对钢筋的缓蚀效率分别达到96.8%和90.0%。该复合缓蚀剂是一种混合型缓蚀剂,对钢筋腐蚀的阴极反应和阳极反应均有抑制作用。     

干湿循环下混凝土中钢筋腐蚀的电化学检测

应用电化学噪声技术,结合电化学阻抗谱研究了干湿循环条件下3种不同pH值的3.5%NaCl溶液中混凝土钢筋的腐蚀过程.结果表明,钢筋的腐蚀分为3个阶段:钝化膜的溶解期、腐蚀活化期和腐蚀产物的累积期.在pH1的溶液中经过30个干湿循环后主要以均匀腐蚀为主,而对pH3和pH7溶液,则主要以点蚀为主,散粒噪声分析证实了混凝土中钢筋在强酸性溶液中更容易发生腐蚀.电化学阻抗谱分析也进一步说明了混凝土中钢筋的腐蚀经历了3个阶段:第1阶段Nyquist谱图中出现两个时间常数,高频区为混凝土层的容抗性质,低频区为钢筋与混凝土界面的电荷转移电阻;第2阶段,中频区增加一个时间常数,这与腐蚀产物的累积有关;第3阶段,随着腐蚀产物向混凝土中的扩散,中频区容抗弧有所减小,特别是pH1体系,中频弧几乎消失.SEM形貌表征观察到随着溶液酸度的增加钢筋表面的锈层明显增多.     

三种有机缓蚀剂对钢筋阻锈作用的电化学研究

应用极化曲线、电化学噪音(EN)和电化学阻抗谱(EIS)等电化学方法,检测和评价N-月桂酰肌氨酸钠、D-葡萄糖酸钠和β-甘油磷酸钠等3种缓蚀剂对钢筋在含NaC l的模拟混凝土孔溶液中电化学腐蚀行为的影响及其阻锈作用.结果表明,D-葡萄糖酸钠对钢筋具有较好的缓蚀效果,其缓蚀作用主要是通过在钢筋表面的竞争吸附和沉积而提高钢筋耐腐蚀性.     

一维阵列电极法研究钢筋在混凝土中的腐蚀行为

建立一维阵列微电极技术,通过对阵列电极腐蚀电位、极化曲线以及微电极之间宏电流的测量,研究在腐蚀环境作用下钢筋混凝土腐蚀过程中宏电池电流和微电池电流的形成、发展及其相互作用.结果表明,腐蚀发生早期,腐蚀宏电池和微电池在不同区域优先形成而且并存.随着腐蚀的发展,受氧扩散控制,在腐蚀宏电池区域出现微电池,而某些腐蚀微电池区域与阴极区耦合,也形成腐蚀宏电池.腐蚀宏电池与微电池电流大小最终趋于一致.     

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.     

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 .     

氯离子对模拟混凝土孔隙液中钢筋腐蚀行为的影响

应用动电位扫描法研究钢筋在模拟混凝土孔隙液中的腐蚀电化学行为以及氯离子的影响作用,并根据阳极极化曲线的变化揭示钢筋表面钝化膜的击穿电位及其变化规律,得出当溶液pH值分别为12.50和12.00时,由氯离子侵蚀引起的钢筋局部腐蚀,其钝化膜击穿电位突降的浓度临界值.     

模拟混凝土孔隙液中钢筋腐蚀的氯离子临界浓度测试

应用扫描微参比电极法,测量钢筋在模拟混凝土孔隙液中的表面微区电位分布;考察在一定pH值时氯离子浓度对溶液中钢筋腐蚀行为的影响。采用逐步逼近法,测试引起钢筋发生点腐蚀的氯离子临界浓度。当溶液pH为12.0时,可以观察到氯离子浓度变化引起钢筋点腐蚀的变化过程,从而确定氯离子浓度临界值为0.04~0.05 mol/L。     

氯离子侵蚀下钢筋在混凝土中腐蚀行为的EIS研究

应用电化学阻抗谱（EIS）和氯离子探针技术，研究在氯化物侵蚀作用下混凝土中钢筋的腐蚀行为.结果表明，钢筋混凝土体系的阻抗谱中包含两个时间常数，分别对应于界面的双电层和钢筋表面的混凝土保护层.自行研制的氯离子探针可连续、无损地测量钢筋/混凝土界面的氯离子浓度.根据腐蚀反应电阻Rct、Warburg阻抗等元件参数和界面氯离子浓度的变化，讨论了混凝土中钢筋腐蚀发生、发展各阶段界面化学环境及钢筋腐蚀参数的变化规律.     

The depth distribution of organic additives in mortar measured with plasma-based Secondary Neutral Mass Spectrometry

Amino alcohols (AMA) have been found to be successful in corrosion prevention of steel-reinforced concrete [1]. However, to work effectively the amino alcohol has to be located at the interface between the concrete and the steel rods reinforcing the stability of the building material [2]. Corrosion prevention for new buildings is easy because the corrosion inhibitor has already been added to the liquid concrete mixture and thus can easily reach the steel rods. With subsequent corrosion prevention measures for existing buildings, however, the problem of transport of the corrosion inhibitor through the solid concrete to the steel surface has to be solved first. In order to determine penetration, transport behavior, and transport rate, an AMA was applied to one face of rectangular mortar blocks used as model samples. A certain period of time for dwelling was given to allow the AMA to penetrate into the mortar. Moreover, the influence of the ambient humidity during the application was investigated. The analysis of the mortar was made by Secondary Neutral Mass Spectrometry, a technique used for the first time for this type of material because of the easy sample preparation, short analysis time, and high sensitivity.     

模拟混凝土孔隙液中D-葡萄糖酸钠复合缓蚀剂对钢筋的阻锈作用

应用电化学技术, 结合扫描电子显微镜(SEM)观测, 研究D-葡萄糖酸钠、钼酸钠和硫脲三组分复合缓蚀剂对模拟混凝土孔隙液中钢筋腐蚀行为的影响及其阻锈作用. 结果表明: 在含3.5% (w) NaCl的模拟混凝土孔隙液中, 复合缓蚀剂具有协同效应, 对钢筋有良好的阻锈作用. 当D-葡萄糖酸钠、钼酸钠和硫脲浓度分别为750、250和500 mg·L^-1时, 对钢筋的缓蚀效率可达到94.5%. 应用软硬酸碱(HSAB)理论分析缓蚀机理, 可认为三组分复合缓蚀剂在钢筋表面共同形成保护膜而阻止钢筋的腐蚀.     

萘系减水剂混凝土钢筋的电化学腐蚀

腐蚀电位监测、线性极化和交流阻抗测试等方法研究混凝土中添加萘系减水剂对钢筋腐蚀行为的影响.发现添加萘系减水剂的混凝土,其电阻和极化电阻大幅增加,其中以添加0.2%萘系减水剂的增幅最明显.适量的萘系减水剂有利于改善混凝土的孔隙结构,增强混凝土的密实性和抗渗透性能,从而减缓混凝土的钢筋腐蚀.     

Fabrication of IrO2 H+ Sensor and Its Application in the Measurement of pH at Steel/Concrete Interface

Corrosion of steel reinforcement is the most serious threat to the service life of modem reinforced concrete structure and the corrosion behavior of the steel reinforcement has a close dependence on the chemical environment at the steel/concrete interface. Among all the species which can affect the corrosion rate, H⁺ is of the greatest influence on the stability of the steel bars. However, the in-situ measurement of pH value at steel/concrete interface is still underway. In this paper fabrication of Ir oxide electrode which serves as the pH probe working at the steel/concrete interface was explored.     

AFM Study on the Surface of Reinforcing Steel in Simulated Concrete Pore Solution

Atomic Force Microscopy (AFM) is a powerful technique to study corrosion processes in the μm- and nm- range because it is able to provide real space images of the surface with high spatial resolution while the operation is simple and fast and the sample is free from exposure to high vacuum atmosphere in which some properties may deviate from those under common pressure. Microscopic study on the topography of the surface layer of passivated metal is of great importance to abstaining better understanding of localized corrosion, especially the early stage of this process. In this paper a systematic AFM study on steel in simulated concrete pore solution (SPS) was carried out in order to illustrate the relationship between the stability of passive film at the surface of the steel and aggressive species in the solution and evaluate the effect of several inhibitors on corrosion resistance of reinforcing steel.     

氯离子侵蚀下钢筋在混凝土中腐蚀行为的EIS研究

应用电化学阻抗谱(EIS)研究环境介质中氯离子对混凝土中钢筋腐蚀行为的影响.结果表明,在测量的频率范围内,钢筋混凝土体系的阻抗谱图包含两个时间常数,分别对应于界面的双电层和钢筋表面的混凝土保护层.其低频段的半圆有些压扁,表明界面双电层的充放电行为偏离理想电容器,可归因于钢筋表面的不均一性.在浸泡后期,低频段出现拖尾,同时电荷转移电阻Rct减小了近两个数量级,这是由于钢筋表面的钝化膜已经破裂,发生活性腐蚀,况且氯离子浓度的增大加速了腐蚀发展过程.讨论了混凝土中在钢筋腐蚀发生,发展的过程中,其腐蚀电位Ecorr以及等效电路中的Rct和Warburg阻抗等元件的变化特征.     

苯并三唑对水泥砂浆中钢筋的阻锈作用

应用腐蚀电位(E_corr)、极化电阻(R_p)和砂浆保护层电阻率(ρ_c)研究了苯并三唑(BTA)对钢筋电极腐蚀电化学行为的影响. 通过电化学阻抗谱(EIS)、循环极化(CP)和循环伏安(CV)结果对比了BTA与NaNO₂ (SN)对钢筋电极在未处理、预锈蚀和内掺氯盐3种状态下3.5% (w)氯盐浸泡360 d后的阻锈效率. 利用环境扫描电镜(ESEM)与能谱分析(EDS)解释了BTA对水泥基材料中钢筋的阻锈机理. 结果表明: 3种状态下BTA均能明显降低砂浆中钢筋的均匀腐蚀速率, 且其阻锈效率高于SN. 在未处理与预锈状态下, BTA抑制点蚀的能力稍弱于SN; 但在内掺氯盐的状态下, BTA表现出了较大的点蚀阻力. BTA除了能在钢筋表面形成复杂的保护膜, 从而有效抑制氯盐的破钝化作用. ESEM/EDS结果表明BTA还能与砂浆基体形成较多富钙C-S-H凝胶, 可能优化了钢筋/砂浆界面区的孔结构, 形成更致密的微观结构, 显著延缓了氯盐向钢筋表面的传输进程, 较好地保护了钢筋. 适量的BTA对砂浆360 d的基本力学性能无明显影响.     

高分子缓蚀剂的合成及其在钢筋混凝土中的应用

合成了硫脲－二乙烯三胺缩聚物（Ｅ－Ｔ）,用动电位极化曲线及电化学阻抗谱研究其在混凝土孔隙模拟液及混凝土中对钢筋腐蚀的抑制作用。结果表明,这是一种混合型缓蚀剂,对钢筋的点蚀也有较好的抑制作用。在模拟液中添加１％该缓蚀剂就可以使氯子的容忍度从０．０２ｍｏｌ／Ｌ提高到０．１０ｍｏｌ／Ｌ,并与ＮａＮＯ２有较好的协同作用。既能吸附于钢筋表面,还能提高混凝土的密实度,减缓电解质渗透。对于钢筋混凝土的腐蚀防护具     

Reinforcing aluminium with cerium oxide: A new and effective technique to prevent corrosion in marine environments

Cerium oxide (CeO₂) is one of the potential choices to be explored for the protection of aluminium from corrosion. However, usage of cerium ions for surface modification of aluminium would not yield any potential effect in aggressive marine environments. Metal matrix composites of aluminium can have all the merits of aluminium such as density, strength, ductility and cost. In the present study, corrosion of aluminium in saline environment was significantly suppressed by means of reinforcing the aluminium with cerium oxide. The presence of cerium oxide in the matrix did not facilitate the formation of Al₂O₃ which would cause potential reshift after few days due to the onset of pitting. The present results strongly lay emphasis on the potential scope of use of CeO₂ for protection of aluminium in marine environments.