常见杂质离子对不锈钢钝化处理的影响

通过在不锈钢钝化处理液中分别添加Cl---、fE--（3+）等常见化学杂质,对18-8不锈钢进行钝化处理,应用电化学方法测量点腐蚀临界电位等腐蚀参数,考察钝化液中化学杂质对不锈钢表面耐蚀处理效果的影响。国家自然科学基

PROGRESS IN ELECTROCHEMICAL TREATMENT APPLIED TO REINFORCED CONCRETE

钢筋混凝土结构的电化学处理技术能有效抑制混凝土碳化和氯化物侵入这两个主要因素引起的混凝土中钢筋的腐蚀,对已经发生去钝化的钢筋具有良好的修复作用,是一种高效率的钢筋混凝土结构修复技术,具有广阔的应用前景.本文论述了该技术的基本原理、处理效果、影响因素及副作用,并提出了评价和建议.The electrochemical treatment technique as a protective method for reinforced concrete structures is reviewed.The technique can effectively inhibit the reinforcing steel corrosion induced by the carbonation of concrete and the chloride ingression and has a bright future for rehabilitation of reinforced concrete structures.In this paper,the mechanism,influencing factors,efficiency and side effects of the electrochemical treatment are presented.国家自然科学基金资助项目(No.20473066);; 国家科技部《重大基础研究(973)前期研究专项》(2005CCA06700

Anticorrosion Properties of Nano Anatase TiO2 Films Derived from Sol-Gel and Hydrothermal Crystallization

Corresponding author. Email: [email protected]; Tel: +86-592-2189354.[中文摘要]以钛酸正丁酯为前驱体,采用溶胶-凝胶-水热晶化法在不锈钢(SS)表面制备TiO2纳米膜.利用X射线衍射(XRD)、Raman光谱、场发射扫描电子显微镜(SEM)、原子力显微镜(AFM)和俄歇电子能谱(AES)表征了TiO2纳米膜的晶型、表面形貌和表面化学组成.通过极化曲线和电化学阻抗谱(EIS)研究了TiO2纳米膜的耐蚀性能.170°C下水热晶化制备的锐钛矿TiO2与450°C焙烧制备的锐钛矿TiO2的结晶度类似,但两种TiO2薄膜的表面结构存在明显差异,水热晶化法制备的TiO2纳米膜在3.5%(w)NaCl溶液中的耐蚀性能优于焙烧法制备的. [英文文摘]Nano TiO2 films were applied to the surface of stainless steel (SS) by sol-gel and hydrothermal crystallization using Ti(O(CH2)3CH3)4 as a precursor. The properties of the TiO2 films were determined by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and Auger electron spectroscopy (AES). The corrosion performance of the TiO2 films was evaluated by electrochemical impedance spectroscopy (EIS) and polarization measurements. Anatase TiO2 films prepared by hydrothermal crystallization at 170 °C showed similar crystallization to those prepared by conventional calcination at 450 °C. The TiO2 prepared by the two methods were, however, obviously different from the surface structure and the material prepared by hydrothermal crystallization showed better anticorrosion performance in 3.5% (w) NaCl solution compared with the material prepared by calcination.国家自然科学基金(50571085,20773100,21003089);国家高技术研究发展专项(2009AA03Z327)资助项

ELECTROCHEMICAL STUDY ON THE EFFECT OF CHLORIDE IONS ON THE PASSIVITY OF REINFORCING STEEL IN SIMULATED CONCRETE PORE SOLUTIONS

通过动电位极化曲线、电化学阻抗潜以及Mott—Schottky曲线的测试,研究了预钝化电位对模拟混凝土孔溶液中钢筋的钝化作用及氯离子对钢筋钝性的影响.结果表明,在室温下相对于饱和甘汞电极电位为-0.200—0.200V范围于不同电位分别预钝化4800 s后,钢筋表面均处于钝态;钝化膜内浅层施主浓度随预钝化电位的升高而减少,深层施主浓度则增加;预钝化电位为0.200 V时,钢筋钝化膜的电荷转移电阻最大;预钝化后的钢筋在含氯离子0.01—0.08 mol/L,pH值为12.50的模拟混凝土孔溶液中浸泡24h后,其表面钝化膜表现为高掺杂的n型半导体,在0.15—0.47 V电位区间内表现为一种类型的施主浓度,施主浓度随氯离子浓度的升高而减小.Potentiodynamic anodic polarization,electrochemical impedance spectroscopy and Mott-Schottky plot were used to study the effect of passive potentials and chloride ion concentrations on the corrosion behavior of reinforcing steel in simulated concrete pore solutions.The results indicated that the compact passive films were formed on the reinforcing steel surface at different passive potentials from -0.200 to 0.200 V vs SCE for 4800 s,with increasing the potential the superficial donor densities decreased but the deep donor densities increased,and the charge transfer resistance of the film reached the highest value at the passive potential 0.200 V.Immersed in simulated concrete pore solutions with chloride ion concentration 0.01—0.08 mol/L and pill2.50 for 24 h,the passive film still behaved as n-type semiconductor,only one type of donor appeared from the Mott Schottky plot,and the deep donor densities decreased with increasing chloride ion concentration.国家自然科学基金项目20473066;; 国家重点基础研究发展计划项目2005CCA06700;; 福建省自然科学基金项目E0210006资助~

FABRICATION OF IrO_2-pH MICROELECTRODE AND ITS APPLICATION IN STUDY OF CHEMICAL MICRO-ENVIRONMENT AT STEEL/CONCRETE INTERFACE

采用电化学阳极氧化和高温碳酸盐氧化两种方法制备IrO2 - pH微电极 ,其特点是对氢离子响应快、线性范围宽、机械性能好、具有长期稳定性 .考察了该电极的 pH响应特性、化学成分、机械性能等 .结果表明 ,这种IrO2 -pH微电极适用于钢筋 /混凝土界面 pH值的原位测量The corrosion behavior of the reinforcing steel has a close dependence on the chemical micro-environment at the steel/concrete interface.In this paper,a kind of IrO 2-pH microelectrode was prepared by anodic electrochemical oxidation and thermal oxidation in carbonate.In the latter case,IrO 2 electrode showed fast linear response,wide linear range(pH 0～14),satisfying mechanical property and long-term stability.The formation of IrO 2 electrode was characterized and the potential response to H + was tested to explore the optimum condition of fabrication of the IrO 2 electrode.The IrO 2-pH electrode was applied for the in-situ measurement of pH at the steel/concrete interface.国家自然科学基金资助项目 (资助号 :5 98710 43

Study on Localized Corrosion Behavior of Reinforcing Steel by Scanning Microelectrode Technique

应用扫描微电极法原位测量了模拟混凝土孔隙液中钢筋表面微区的电位分布,并结合动电位极化曲线的测量,研究了钢筋的局部腐蚀行为及模拟混凝土孔隙液pH值和Cl-浓度对它的影响.结果表明,在饱和Ca(OH)2溶液中,钢筋处于钝态,其表面微区电位分布为动态平衡;溶液的pH值降低和外加一定浓度的Cl-后,钢筋表面微区电位分布随之变化.当表面微区电位分布出现固定的突出电位峰时,钢筋发生了点腐蚀.在pH=12.00,外加Cl-浓度为0.05 mol/L或pH值降至10.16的Ca(OH)2溶液中,钢筋表面去钝化,发生腐蚀.In this work,the scanning microelectrode technique and potentiodynamic polarization were used to study the localized corrosion behavior of the reinforcing steel in simulated concrete pore solution with different pH values and chloride ion concentrations.It has been found that the reinforcing steel bar exhibits different corrosion characteristics in different conditions.There are some unstable micro-pitting nuclei on the surface of the steel in pure saturated Ca(OH)_2 solution and the steel remains passivated.However,the potential distribution on the steel surface changes with the addition of Cl~-or/and the reduction of pH value in the solution.The pitting corrosion of the steel occurs quickly when there are some obvious stable potential peaks on the steel surface and the height of one or some maximum potential peaks increases with time.Steel depassivation initiates and the corrosion takes place when additional Cl~-concentration reaches 0.05 mol/L in the Ca(OH)_2 solution with pH=12.00 or the pH of the solution falls to 10.16.国家自然科学基金资助项目(20473066);; 福建省自然科学基金资助项目(E0210006);; 国家重点基础研究前期研究专项项目(2005CCA06700

电沉积钙磷盐涂层及其影响因素的研究

发展在低温下电沉积钙磷盐的方法,制备了可以提高医用钛表面生物活性的涂层。考察了电流密度和温度的变化对涂层性质和形貌的影响,并应用扫描电镜(SEM)、X射线衍射(XRD)、傅立叶-红外光谱(FT-IR)对合成的生物材料进行分析和表征,探明了电沉积钙磷盐涂层主要因素的影响作用。结果表明,反应温度可导致钙磷盐涂层的形貌和组成的变化,电流密度则影响钙磷盐晶体的生长方向

扫描复合微pH电极原位测量局部腐蚀体系pH分布图象

金属点腐蚀是一种典型的局部腐蚀，点腐蚀过程不仅与金属相组分、夹杂及表面状态等有关，而且与许多环境因素密切相关，其中在金属／溶液界面Ｃｌ－浓度和ｐＨ的分布是影响金属点腐蚀发生、发展过程最为重要的微化学环境因素．研究点腐蚀过程中金属／溶液界面微化学环境对于了解点腐蚀机理及过程动力学具有重要的意义．本文首次研制成功复合型ＩｒＯ２／ＰｔｐＨ电极，复合微电极是ＩｒＯ２／ＰｔｐＨ微探针和ＡｇＣｌ／Ａｇ（ＫＣｌ）微参比电极组成．实验表明，复合型ＩｒＯ２／Ｐｔ微ｐＨ电极对ｐＨ值有良好的线性关系，测量灵敏度高，并可补偿局部腐蚀电位差异的影响，能够原位检测靠近金属／溶液界面二维方向微区ｐＨ值的分布图象．结合微区电位分布测试仪测量了不锈钢点蚀过程，金属／溶液界面二维方向微区ｐＨ值及其变化，探索了点腐蚀发展过程机理．扫描复合型ｐＨ微电极可成为原位研究金属局部腐蚀发生、发展过程机理的一种重要方法作者联系地址：物理化学研究所,固体表面物理化学国家重点实验室,厦门大学,Ａｌｂｅｒｔａ大学化学和材料工程

ELECTROCHEMICAL TECHNIQUES WITH SPATIAL RESOLUTION IN RESEARCH of LOCALIZED CORROSION of METALS

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,使得人们对金属表面和金属/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得以深化.The electrochemical inhomogeneities at interface of metal/solution play an important and often controlling role in localized corrosion of metals.The traditional electrochemical techniques involving potential, current density or AC impedance measurements over bulk specimens can only provide average and whole information.It is necessary to develop in situ imaging techniques for further characterizing electrochemical inhomogeneities at the interface of metal/solution of localized corrosion system.The eletrochemical techniques with spatial resolution, including scanning single micro electrode, scanning double micro electrodes and scanning micro chemical probes have been reviewed.The effects of the electrochemical inhomogeneities on the corrosion behavior and mechanism of various localized corrosion of metals have been further understood by appropriately using these new electrochemical techniques.国家自然科学基金资助项

Photogenerated Cathodic Protection Properties of a TiO_2 Nanowire Film Prepared by a Hydrothermal Method

Corresponding author. Email: [email protected]; Tel: +86-592-2189192.[中文文摘]应用水热法在钛箔表面制备TiO2纳米线薄膜,采用场发射扫描电子显微镜、X射线衍射和紫外-可见分光光度法对薄膜进行表征,用电极电位和电化学阻抗谱考察TiO2光生阴极保护性能.结果表明:薄膜由纵横交错的锐钛矿型TiO2纳米线组成,纳米线的直径约10nm.在150℃下反应6h生成的TiO2纳米线薄膜在0.3mol·L-1 Na2SO4溶液和0.3mol·L-1 Na2SO4+0.5mol·L-1 HCOOH混合溶液中对与TiO2薄膜耦连的403不锈钢均有良好的阴极保护效应.TiO2膜所在溶液中含有HCOOH时,可使耦连的403不锈钢在0.5mol·L-1 NaCl溶液中电极电位负移约545mV,界面反应电阻显著变小,表明电解质溶液加入HCOOH可以增强TiO2纳米线薄膜对403不锈钢的光生阴极保护效应.[英文文摘]A TiO2 film was synthesized on the surface of a Ti substrate by a hydrothermal method,followed by acid treatment and calcination.The properties of the TiO2 film were characterized by scanning electron microscopy,X-ray diffraction,and ultraviolet-visible spectrophotometry.The photogenerated cathodic protection properties of the TiO2 film were investigated by electrochemical techniques.The corrosion performance of 403 stainless steel coupled to a TiO2 film photoanode in different solutions was evaluated by photogenerated potential and electrochemical impedance spectroscopy. The results showed that the TiO2 film was composed of many randomly-oriented anatase nanowires of about 10 nm in diameter. The TiO2 nanowire film prepared by the hydrothermal reaction at 150 ℃ for 6 h was used for the photogenerated cathodic protection of 403 stainless steel. When we coupled the steel in a 0.5 mol·L -1 NaCl solution to the TiO2 film photoanode in a mixed solution containing 0.3 mol·L-1 Na2SO4 and 0.5 mol·L-1 HCOOH, its potential decreased by 545 mV. Additionally, the charge transfer resistance of the electrode reaction process for the coupled steel decreased considerably. The results also indicated that the HCOOH in the mixed solution improved the photogenerated cathodic protection of the TiO2 film photoanode.国家高技术研究发展专项(2009AA03Z327); 国家科技支撑计划项目(2007BAB27B04)资