扫描电化学微探针的发展及其在局部腐蚀研究中的应用

简要概述当前国内外具有空间分辨能力的扫描微探针技术及其在腐蚀研究中的应用,包括扫描微电极技术(SMET)、扫描电化学显微镜(SECM)、原子力显微镜(AFM)、扫描Kelvin探针技术(SKP)等,其中SMET、SECM、SKP及局部交流阻抗技术可直接测定腐蚀电极表面或界面电化学不均一性的分布图像,而原子力显微镜技术则是通过分子间作用力从纳米尺寸测量腐蚀过程表面形貌的变化.文中侧重介绍作者近年先后建立的具有微米空间分辨度的电化学微探针技术,并利用各种扫描探针技术研究金属/溶液界面电化学不均一性及其局部腐蚀过程.研究表明,空间分辨电化学方法的发展及应用,加深了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、发展及过程机理的认识.     

扫描电化学显微镜原位表征pH值对核电蒸汽发生器合金腐蚀行为的影响(英文)

用扫描电化学显微镜(SECM)和电化学阻抗谱(EIS)原位表征了溶液pH值对核电蒸汽发生器800合金溶液中的腐蚀行为的影响.实验结果表明:在酸性氯化钠溶液中,SECM探针渐进曲线为正反馈,表明800合金为活化阳极溶解,腐蚀电位下的EIS图呈现完整的单容抗弧特征;而在中性或者碱性溶液中,SECM探针渐进曲线为负反馈,表明800合金为自钝化,不同阳极电位下的EIS图均呈现不完整的容抗弧特征,但随着阳极极化电位的增加,EIS谱容抗弧半径减小,表明钝化膜的耐蚀性下降;SECM二维扫描图像结果显示探针电流增加,表明电极表面活性增加,即钝化膜的溶解速度增加.而在中性或者碱性溶液中的SECM二维图像中均可观察到若干活性点,这可能与晶界或者金属夹杂物等有关.     

扫描电化学显微镜原位表征pH值对核电蒸汽发生器合金腐蚀行为的影响

用扫描电化学显微镜(SECM)和电化学阻抗谱(EIS)原位表征了溶液pH值对核电蒸汽发生器800 合金溶液中的腐蚀行为的影响. 实验结果表明：在酸性氯化钠溶液中,SECM探针渐进曲线为正反馈,表明800合金为活化阳极溶解,腐蚀电位下的EIS 图呈现完整的单容抗弧特征;而在中性或者碱性溶液中,SECM探针渐进曲线为负反馈,表明800 合金为自钝化,不同阳极电位下的EIS 图均呈现不完整的容抗弧特征,但随着阳极极化电位的增加,EIS 谱容抗弧半径减小,表明钝化膜的耐蚀性下降;SECM二维扫描图像结果显示探针电流增加,表明电极表面活性增加,即钝化膜的溶解速度增加. 而在中性或者碱性溶液中的SECM二维图像中均可观察到若干活性点,这可能与晶界或者金属夹杂物等有关.     

覆铜板在NaCl溶液中的腐蚀电化学行为

应用线性极化、循环伏安(CV)及电化学阻抗谱(EIS)等电化学方法对覆铜板(CCL)和纯铜的腐蚀电化学行为进行了研究和比较. 结果表明, 覆铜板的耐蚀性弱于纯铜, 其阳极溶解过程与纯铜有所不同; 在较低电位下, CCL 以铜的氯化络合物的形式溶解, CuCl-2的扩散为该过程的控制步骤; 随着电位的升高, 腐蚀产物CuCl在电极表面形成疏松多孔的膜, Cl-在膜中的传输成为溶解过程的控制步骤. 电极表面CuCl 膜的消长过程是产生感抗弧的主要原因.     

有机涂层／金属界面腐蚀的微区电化学

以扫描开尔文探针，局部交流阻抗和扫描电化学显微镜为代表的微区电化学技术以其高精度、高空间解析度的定域分析优势被广泛应用。本文简要介绍了这三种技术的测量原理和关键问题，并着重归纳了这些技术应用于有机涂层／金属界面腐蚀行为的研究成果，包括界面微区表观形貌的获取，不同界面腐蚀机制的推理验证及其影响因素的作用机理等，并对三种技...     

Ca掺杂的CeO2模型催化剂的形貌和电子结构及其与CO2分子的相互作用

利用扫描隧道显微镜、X射线光电子能谱和同步辐射光电子能谱研究了CeO₂(111),部分还原的CeO_2-x(111) (0＜x＜0.5)以及Ca掺杂的CeO₂模型催化剂的形貌、电子结构以及它们与CO₂分子间的相互作用。CeO₂(111)和部分还原的CeO_2-x(111)薄膜外延生长于Cu(111)单晶表面。不同Ca掺杂的CeO₂薄膜是通过在CeO₂(111)薄膜表面室温物理沉积金属Ca及随后真空退火到不同温度而得到的。不同的制备过程导致样品具有不同的表面组成,化学态和结构。CO₂吸附到CeO₂和部分还原的CeO_2-x表面后导致表面羧酸盐的形成。此外,相比于CeO₂表面,羧酸盐物种更易在部分还原的CeO_2-x表面生成,而且更加稳定。而在Ca掺杂的氧化铈薄膜表面,Ca²⁺离子的存在有利于CO₂的吸附,且探测到碳酸盐物种的形成。     

海洋微生物对316不锈钢的电化学腐蚀行为

采用自腐蚀电位、电化学极化曲线、电化学阻抗谱技术研究了316不锈钢在无菌培养基介质和海水微生物接种培养有菌培养基介质中不同周期的腐蚀行为．结果表明,316不锈钢电极在有菌介质中比在无菌介质中的腐蚀电流密度大,腐蚀电位负移,微生物加速了不锈钢的腐蚀速度．随着浸泡时间的增加,有菌介质中的不锈钢电极极化电阻值逐渐减小,表明了海洋微生物的附着和繁殖加速了316不锈钢的腐蚀速率,降低了其在海洋环境中的耐蚀性．     

抑制Q235钢CO2腐蚀的气液双相咪唑啉衍生物缓蚀剂的缓蚀行为

采用失重法、交流阻抗(EIS)及傅里叶变换红外光谱(FT-IR)、原子力显微镜(AFM)、X射线光电子能谱(XPS)等表面分析测试方法首次研究了硫脲基咪唑啉衍生物(TAI)作为抑制CO₂腐蚀的气液双相缓蚀剂的缓蚀行为. 结果表明, 该硫脲基咪唑啉缓蚀剂能有效地抑制Q235 钢在气液双相中的CO₂腐蚀. AFM测试结果表明该缓蚀剂能显著地降低碳钢表面的腐蚀破坏, 并且由于碳钢表面形成的缓蚀剂吸附膜的疏水作用,可在AFM探头和碳钢表面之间检测到更大的粘附力, 而探针与试样表面之间的长程静电斥力在气相中增加,在液相中由于表面电荷的屏蔽效应而减小. XPS和FT-IR 光谱测试表明液相中和气相中在碳钢表面形成吸附膜的缓蚀剂成分分别是硫脲基咪唑啉衍生物和其酸水解产物——酰胺. 以上结果也进一步证实了咪唑啉衍生物在酸性溶液中的水解机理.     

碳钢在微生物介质中的腐蚀电化学行为

硫酸盐还原菌（SRB）生长代谢，溶液pH值从7．5下降到5．8，并在碳钢表面形成生物膜，改变了生物膜下碳钢表面的微环境，促进碳钢点蚀的形成，清除表面的腐蚀产物后，碳钢基体表面为分布不均匀的溃斑，发生严重的点蚀行为，而RB的活性和生物膜的结构诱发碳钢腐蚀的形成和生长，在微生物快速生长过程中出现明显的氢扩散电流峰，加剧碳钢的渗氢行为，采用电化学阻抗（EIS）研究了碳钢在微生物腐蚀过程中生物膜的结构与腐蚀相应的变化关系。     

Corrosion behavior of CoCrMoW cast alloy in lactic acid environment for surgical applications

The corrosion behavior of CoCrMoW alloy in lactic acid environment during 168 h of immersion at 37 °C has been studied and assessed by means of electrochemical techniques (open circuit potential (OCP), potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS)). Further, the oxide film thickness formed after immersion and the quantity of ions released have been evaluated by X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical spectroscopy (ICP-OES). A good correlation between the results, related to the oxide film thickness, obtained from these experimental techniques was achieved. The research has also shown that the tendency of growing of oxide film becomes slower as the time of immersion is longer. The higher corrosion resistance of CoCrMoW alloy in lactic acid environment is due to the formation of the oxide film highly enriched in Cr(III) on the alloy surface. With a small corrosion rate, e.g. 45 nm year⁻¹, this alloy is characterized as “Perfect Stable” according to ISO 8044/2000. Overall, the present study provides additional evidences with respect to the benefic influence of tungsten on passivity, explained by a higher resistance to pitting corrosion of the CoCrMoW alloy in lactic acid with sodium chloride.     

弱碱性介质中氯离子对铜电极腐蚀行为的影响

应用循环伏安法、X射线光电子能谱法、电化学阻抗谱法以及现场椭圆偏光法研究了在弱碱性介质中添加Cl－对铜电极腐蚀行为的影响.结果表明, Cl－的加入能加剧铜电极的腐蚀,使腐蚀电流以及现场椭圆偏振参数Δ的变化范围都增大1个数量级, Cl－对Cu2O的掺杂将使铜电极的表面膜变得疏松,膜的耐蚀性变差.椭圆偏光实验不仅与电化学和能谱实验的结果一致,而且还能定性地、清楚地分辨出铜电极腐蚀过程中Cu2O的生成、Cl－对Cu2O的掺杂、CuO的生成等不同阶段;同时,利用恰当的模型还能定量地确定各个阶段铜电极表面膜的组成、厚度的变化,从而为研究铜电极的腐蚀与防护机理提供更多有用信息.     

酸性介质中羧甲基纤维素钠在低碳钢表面的吸附和缓蚀作用

The effect of sodiumcarboxymethyl cellulose (Na-CMC) on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl solution has been investigated by using weight loss (WL) measurement, potentiodynamic polarization, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) methods. These results showed that the inhibition efficiency of Na-CMC increased with increasing the inhibitor concentration. Potentiodynamic polarization studies revealed that the Na-CMC was a mixed type inhibitor in 1.0 mol·L-1 HCl. The adsorption of the inhibitor on mild steel surface has been found to obey the Langmuir isotherm. The effect of temperature on the corrosion behavior of mild steel in 1.0 mol·L -1 HCl with addition of 0.04% of Na-CMC has been studied in the temperature range of 298-328 K. The associated apparent activation energy (E*a) of corrosion reaction has been determined. Scanning electron microscopy (SEM) has been applied to investigate the surface morphology of mild steel in the absence and presence of the inhibitor molecules.     

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.     

Electrochemical behaviour of Ni-Co amorphous alloys in alkaline solutions

The dissolution processes of amorphous G15 (Ni₅₈Co₂₀B₁₂Si₁₀) and G16 (Ni₂₅Co₅₀B₁₀Si₁₅) alloys in carbonate-bicarbonate buffers (8.9≤pH≤10.5) have been studied using voltammetry and stationary polarization techniques combined with electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. Results indicate that the electrochemical processes are dependent on the applied potential, the alloy composition, and the pH and ionic strength of the electrolyte. An enhancement of the corrosion processes is observed when the pH and the ionic strength are increased and when the Co content of the alloy diminishes. Furthermore, XPS provided information about the composition of the surface layer. Electronic Publication     

Adsorption Behavior and Inhibition Corrosion Effect of Sodium Carboxymethyl Cellulose on Mild Steel in Acidic Medium

The effect of sodium carboxymethyl cellulose (Na-CMC) on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl solution has been investigated by using weight loss (WL) measurement, potentiodynamic polarization, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) methods. These results showed that the inhibition efficiency of Na-CMC increased with increasing the inhibitor concentration. Potentiodynamic polarization studies revealed that the Na-CMC was a mixed type inhibitor in 1.0 mol·L-1 HCl. The adsorption of the inhibitor on mild steel surface has been found to obey the Langmuir isotherm. The effect of temperature on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl with addition of 0.04% of Na-CMC has been studied in the temperature range of 298-328 K. The associated apparent activation energy (E*a ) of corrosion reaction has been determined. Scanning electron microscopy (SEM) has been applied to investigate the surface morphology of mild steel in the absence and presence of the inhibitor molecules.     

Adsorption Behavior and Inhibition Corrosion Effect of Sodium Carboxymethyl Cellulose on Mild Steel in Acidic Medium

The effect of sodium carboxymethyl cellulose (Na-CMC) on the corrosion behavior of mild steel in 1.0 mol·L⁻¹ HCl solution has been investigated by using weight loss (WL) measurement, potentiodynamic polarization, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) methods. These results showed that the inhibition efficiency of Na-CMC increased with increasing the inhibitor concentration. Potentiodynamic polarization studies revealed that the Na-CMC was a mixed type inhibitor in 1.0 mol·L⁻¹ HCl. The adsorption of the inhibitor on mild steel surface has been found to obey the Langmuir isotherm. The effect of temperature on the corrosion behavior of mild steel in 1.0 mol·L⁻¹ HCl with addition of 0.04% of Na-CMC has been studied in the temperature range of 298–328 K. The associated apparent activation energy (E^*_a) of corrosion reaction has been determined. Scanning electron microscopy (SEM) has been applied to investigate the surface morphology of mild steel in the absence and presence of the inhibitor molecules.     

用于超级电容器电极材料的聚苯胺基碳(英文)

在不同温度下碳化硫酸掺杂的聚苯胺制备了含杂原子(氮和氧原子)的新型碳材料.分别通过扫描电镜、元素分析仪、X射线光电子能谱仪和比表面积测试仪对这些碳材料的形貌特征、元素组成、表面化学组成和比表面积进行了表征.用循环伏安法、恒电流充放电法和交流阻抗法对其进行了电化学性能的研究.研究结果表明,在温度为800℃下碳化聚苯胺得到的碳有很好的电化学性能,尽管它的比表面积很小(325m·2g-1),但在0.5A·g-1电流密度下其比电容高达153F·g-1.它的高比电容可能与其含有合适比例的杂原子(氮和氧原子)有关,因为合适比例的氮和氧杂原子能够产生最大的赝电容.这些结果表明这种碳材料是一种很有发展前景的超级电容器电极材料.