Name: potentiodynamic corrosion testing
Uploaded: 2016-09-04T14:00:00.000+00:00
Duration: 8 min 43 s
Description: Watch this Scientific Journal Video about Potentiodynamic Corrosion Testing at JoVE.com

The authors had no funding provided for this study.

1.样品架的构建<ol><li>构造由不锈钢隔板和M3的不锈钢牙螺钉，代替与M3的六角螺母保持的样品架。 </li><li>用钳子取出螺纹螺钉的头部和抛光切段维持螺纹图案。 </li><li>当所有单独的组件已经准备好，组装电极夹。每个电极夹包含从而导致11.5厘米手柄的M3螺丝连接在一起的三个间隔。放置六角螺母在螺杆和隔板的接合以锁定连接。 </li><li>焊料（60/40％的Sn / Pb）无牙鳄鱼夹到在杆的端部的螺钉。这将确保牢牢把握分析过程中稍后再连接电极。 </li><li>一旦电极座组装，适用停止过漆（电气密封胶）的多道涂层，以防止不锈钢棒被腐蚀，而沉浸在腐蚀室中。 <ol><li>将所有电极持有人连接到鳄鱼夹入前涂通风柜样本。放置20毫升注射器进入通风柜。用注射器收集停止过漆。 </li><li>打开通风柜，倒停过漆成一个小玻璃瓶。拉10毫升停止断漆到注射器和涂布电极夹头的表面上。确保不覆盖测试样品，这是将要分析的腐蚀。 </li><li>在通风柜每个电极架和地点的涂层一半涂覆，另一半之前干燥。这将有助于获得一个完整的密封良好涂层而不损坏要被涂敷的区域。确保在干燥阶段，新涂的区域不碰其他表面，因为这会毁了应用外衣。 </li><li>放在一个高的位置，电极持有人不接触任何表面的干燥过程。外套由于停止过漆的快速凝固电极快。这样就完成了第一层。 </li><li>一旦干燥，重复该过程，得到3外套沿整个区域。 </li></ol></li><li>在开始运行腐蚀之前，离开人最后一层完成后晾干24小时。所有涂层过程发生在RT，不加热或冷却步骤需要，尽管它们可能加速/减速固化过程。 </li><li> 制造法拉第笼 <ol><li>通过涂布相同大小的两个塑料容器4层铝箔覆盖所有侧面构造的法拉第笼。 </li><li>切两个小孔列于上部塑料容器的边缘，以允许所述电极连接到恒电位仪和氮气管线的氮气罐通过。法拉第笼的分割设计允许在运行结束要删除的上部件，而无需更换下部部分容纳罐。 </li><li>适合外室（水室）插入法拉第笼。 LEAVE在仅当腐蚀容器已经被密封的（在后面的步骤）的下隔室的顶部下半年侧和地点。 </li></ol></li></ol> 2.玻璃器皿清洗<ol><li>每腐蚀运行前清理腐蚀容器（700毫升圆柱瓶）。擦洗家用洗涤剂的容器中，用自来水彻底冲洗。重复此步骤3次。 </li><li>冲洗腐蚀容器用去离子水（DI）水洗涤3次以除去自来水中发现的潜在的污染物。 </li><li>一旦用DI水漂洗完成倾300毫升95％乙醇的进腐蚀容器，摇动周围接触所有内表面。倒出乙醇，重复此步骤3次。 </li><li>发表通风橱下的耐蚀容器30分钟，以允许所有的乙醇完全蒸发。 </li><li>取干净，干燥腐蚀容器中，并与将被用于腐蚀运行电解质冲洗。前面ACH冲洗填充用200ml电解质的腐蚀容器中，并重复此过程3次。在这项研究中，漂洗用磷酸盐缓冲盐水（PBS）的腐蚀容器中。 PBS的通篇使用（10升）的电解质的化学组成为80克NaCl，11.5克Na 2 HPO 4，2克氯化钾和2g KHPO 4。 </li><li>以下漂洗，填充用PBS的所需体积准备用于反应的腐蚀容器中。 </li></ol> 3.设备的安装<ol><li>夹持加热器与一个内置循环系统用夹具的外隔室的一侧。外室的大小需要是大约30厘米×20厘米×20厘米，由玻璃或聚合物的以能够壳体较小腐蚀容器和加热器系统。 </li><li>填用自来水外室，直到水的水平高于腐蚀容器内的悬浮电极的高度高。较小的隔室是腐蚀容器（以前在第2描述的）。 </li><li>用密封的玻璃反应盖腐蚀容器夹，以确保防水密封。腔室的盖子提供了实验和测定装置6的入口点。 </li><li>暂停从反应盖的入口点中的一个温度计，以提供腐蚀电池内部的温度的读数。暂停从盖子使用其他3个入口点的所有三个电极。使用聚四氟乙烯（PTFE）胶带，以确保每个连接的密封。 </li><li>使用三电极结构，包括一个参考，计数器，和工作电极。工作电极是不锈钢螺钉（下分析样品）。插入电极插入腐蚀容器之前，擦拭用80％的乙醇浸泡在填充用100ml的PBS的玻璃烧杯擦拭和地点。 </li><li>使用连接引脚到电极夹附着到电极上吊带。适合该电极Ë吊带进入腐蚀容器的盖子的入口点。 </li><li>放置在工作电极中央与计数器和参考电极从任一侧被暂停。密封玻璃入口，并使用聚四氟乙烯带腐蚀吊带。 </li><li>为参考电极，使用一个标准的Ag / AgCl。对电极，使用铂网状这是松散弯曲包裹试样围绕被测（工作电极）。 </li><li>填用吸管用3M氯化钾的银/氯化银电极。经过广泛的使用，变更和填充银银/氯。要做到这一点释放电极尖端空出的流体成一个小玻璃收集容器（烧杯）。一旦所有的溶液是去除插入尖端和用3M氯化钾填充。 </li><li>使用上的所有路口磁带确保整个室是密封的。 </li><li>一旦该腔室被放置在腐蚀容器内所有电极密封，将温度设定为37℃，并打开氮气阀机智哈流量为150 立方厘米 / min的速率。在进行运行前留下60分钟的温度和氮气运转。保持氮气运行在实验的持续时间。 </li></ol> 4.运行腐蚀试验<ol><li>打开电化学软件包，其与USB控制电位接口。 </li><li>制作和3个电极恒电位仪之间的电气连接，然后打开电位上。 </li><li>打开并使用"测量视图"来查看腐蚀环境的潜力和电流读数。期间在没有斜坡电位尚未施加工作（正电位）和计数器之间的电流读数的开路电势（OCP）相（负）电极是围绕（0±0.01）微安。用PTFE带腔室的不当密封可能会导致在当前读数的波动，由于该腔室被用氮气充气至除去氧分子。 </li><li>离开样以平衡，腐蚀容器环境中稳定。这个持续时间而变化（1至6小时），并依赖于材料。监视用的测量，以确定是否达到了稳定的条件的可能性。一旦达到稳定的条件下的电位将与无波动恒定。 </li><li>后稳定条件达到，开始腐蚀运行。不过在此之前可以做到的，填写"腐蚀计划"和"循环伏安法（CV）"的条件下利用分析软件提供的框架模板。 </li><li>从程序选项卡中设置视图中的循环伏安恒电位的过程。 </li><li>启用以下参数腐蚀运行进行采样:时间，工作电极（WE）电位，电流腐蚀运行。 </li><li>选择自动电流范围的选项。设置的最高电流的范围为10毫安，并在R的最低电流安格成为了WE 10 nA的。 </li><li>确保最终截止选择由设置&#39;循环回&#39;参数至0.8毫伏，以允许磁滞回线来完成通过电位控制。 </li><li>从测量视图进入OCP参数文本框中记录OCP。设置下面的记录OCP值开始潜力100毫伏。设置上限顶点电位至800毫伏，下部顶点到100毫伏下开始电位和停止电势为100毫伏低于下顶点潜力。设置扫描速率到0.001伏/秒和步潜力0.0024 V /秒。现在，按启动键。 </li></ol> 5.腐蚀运行完成后注意:在腐蚀结束运行偏振扫描软件的分析视图中示出。对于每一个极化运行演示者视图列出了OCP，该地块对于E与T和CV楼梯，为E主场迎战日志（I）的情节。 <ol><li>在每个情节升墨，确定数据点的内部过滤，塔菲尔外推，和情节的选项。展开向显示感兴趣的各种参数，它们共同形成了电化学参数的每一个环节。极化扫描（电流密度-电势），确定开路电位，点蚀电位（E 坑 ）和保护电势（E 亲 ）。 </li><li>制表使用塔菲尔斜率链路的腐蚀速率下的阳极和阴极塔菲尔常数，腐蚀速率，腐蚀电流，腐蚀电流密度，起始电位，结束电位。 </li></ol> 6.删除从电极保持样品<ol><li>准备在通风橱下50毫升二氯甲烷3小罐。 </li><li>由浸渍保持件的下端的二氯甲烷为一个通风橱内30分钟除去由电极支架测试的样品。 </li><li>一旦分离，将试样进入下一个罐子二氯甲烷和离开15分钟。重复此过程，与第三和最后冲洗摆脱在样品上的安装部分的任何多余的涂料。 </li><li>擦拭从剪辑和样本剩余的密封胶，最后用去离子水冲洗。 </li></ol>

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M. a. t. e. r. .. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+corrosion+of+modular+hip+prosthesis+components+in+mixed+and+similar+metal+combinations.+The+effect+of+crevice,+stress,+motion+and+allot+coupling.">In vivo corrosion of modular hip prosthesis components in mixed and similar metal combinations. The effect of crevice, stress, motion and allot coupling.</a> J. Biomed. Mater. Res. 76 (1), 1533-1544 (1993).</li><li>Browne, J. A., Bechtold, C. D., Berry, D. J., Hanssen, A. D., Lewallen, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Failed+metal-on-metal+hip+arthroplasties:+a+spectrum+of+clinical+presentations+and+operative+findings.">Failed metal-on-metal hip arthroplasties: a spectrum of clinical presentations and operative findings.</a> Clin. Orthop. Relat. Res. 468 (9), 2313-2320 (2010).</li><li>Jantzen, C., Jorgensen, H. L., Duus, B. R., Sporring, S. L., Lauritzen, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chromium+and+cobalt+ion+concentrations+in+blood+and+serum+following+various+types+of+metal-on-metal+hip+arthroplasties:+a+literature+overview.">Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties: a literature overview.</a> Acta Orthop. 84 (3), 229-236 (2013).</li><li>Frangini, S., De Cristofaro, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+galvanostatic+polarisation+method+for+determining+reliable+pitting+potentials+on+stainless+steels+in+crevice-free+conditions.">Analysis of galvanostatic polarisation method for determining reliable pitting potentials on stainless steels in crevice-free conditions.</a> Corros Sci. 45 (12), 2769-2786 (2002).</li></ol>

The authors have nothing to disclose.

从不锈钢试样产生偏振扫描显示清洁连续曲线，在指示运作良好的腐蚀系统，该系统既可靠和可再现29的文献看出扫描相关联。差电位点蚀电位的再现性是确定与几百毫伏的蔓延，与孔蚀电位的特征在于一个随机过程29。这通常是由于温度，卤化物含量和电势（V）的变量;因此，从实际安装在E 科尔获得较小的变化是指示协议，并具有改善体外设置上述调整。 <p cla...

电化学技术提供了快速且相对便宜的方法获得的材料的电化学性能。这些技术在通过观察电荷转移过程的受控电化学干扰1-5的响应，以检测金属的腐蚀的能力，主要是基础的。体的环境中的金属植入物的腐蚀是非常关键的，由于在生物相容性和材料完整性6的不利影响。促进身体内植入物的腐蚀的主要因素是表面氧化，导致金属离子7-11的释放增多的溶解。这将导致不良的生物反应，其可以发现局部的，但具有潜在的全身效应，导致植入物10,12-28的过早失效。 试样的腐蚀特性从产生的偏振扫描预测由恒电位。偏振扫描允许对金属基板的动能和腐蚀参数的推断。在扫描期间，氧化或还原的电活性物种可以通过电荷转移和反应物或产物的运动受到限制。这些因素都是由偏振扫描包封;因此具有在多个周期产生一个可靠和可重复的偏振扫描系统的重要性是非常重要的。这份手稿的重点是提供一个确定的协议，以获得一个运作良好的电位腐蚀体系所采取的基本原理和步骤。

<table><tbody><tr><td>Potentiostat</td><td>Metrohm</td><td>PGSTAT101</td><td></td></tr><tr><td>Ag/AgCl reference electrode, shielded</td><td>Metrohm</td><td>6.0729.100</td><td></td></tr><tr><td>Electrode shaft</td><td>Metrohm</td><td>6.1241.060</td><td></td></tr><tr><td>Polisher Forcipol 1v</td><td>Metkon</td><td>3602</td><td></td></tr><tr><td>Clindrical flask 700 ml</td><td>SciLabware</td><td>FR700F</td><td></td></tr><tr><td>Reaction lid</td><td>SciLabware</td><td>MAF2/41</td><td></td></tr><tr><td>Dichloromethane</td><td>Sigma-Aldrich</td><td>MKBR7629V</td><td>Use under a fumehood. Wear protective clothing.</td></tr><tr><td>Thermo / HAAKE D Series Immersion Circulators</td><td>Haake</td><td></td><td></td></tr></tbody></table>

potentiodynamic corrosion testing

Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation potential of the material. The detection of these electrochemical parameters identifies the corrosion factors of a material. A reliable and well-functioning corrosion system is required to achieve this.
Corrosion of the samples was achieved via a potentiodynamic polarization technique employing a three-electrode configuration, consisting of reference, counter, and working electrodes. Prior to commencement a baseline potential is obtained. Following the stabilization of the corrosion potential (Ecorr), the applied potential is ramped at a slow rate in the positive direction relative to the reference electrode. The working electrode was a stainless steel screw. The reference electrode was a standard Ag/AgCl. The counter electrode used was a platinum mesh. Having a reliable and well-functioning in vitro corrosion system to test biomaterials provides an in-expensive technique that allows for the systematic characterization of the material by determining the breakdown potential, to further understand the material's response to corrosion. The goal of the protocol is to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices.

在该过程结束体外腐蚀系统设置进行腐蚀研究。如腐蚀容器和法拉第笼的清洁特定程序被引入协议来改善噪声性能。一个良好的偏振扫描的基本概念是，以确定以理解的金属材料的腐蚀敏感性提供有价值的信息，该材料的电物理条件。的程序和协议，以实现可靠的和可重复的结果是至关重要的。获得其上的优化可以帮助，可以在使用过程中出现的某些问题的信息，?...

Watch this Scientific Journal Video about Potentiodynamic Corrosion Testing at JoVE.com

Potentiodynamic Corrosion Testing

Here, we present a protocol to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices.

动电位腐蚀试验

Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation ...

Research

JoVE Journal

Environment

17.5K 次观看.  Prince of Wales Clinical School. Here, we present a protocol to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices. 

视频: Potentiodynamic Corrosion Testing

Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media

Material corrosion can be a limiting factor for different materials in many applications. Thus, it is necessary to better understand corrosion processes, prevent them and minimize the damages associated with them. One of the most important characteristics of corrosion processes is the corrosion rate. The measurement of corrosion rates is often very difficult or even impossible especially in less conductive, non-aqueous environments such as biofuels. Here, we present five different methods for the determination of corrosion rates and the efficiency of anti-corrosion protection in biofuels: (i) a static test, (ii) a dynamic test, (iii) a static test with a reflux cooler and electrochemical measurements (iv) in a two-electrode arrangement and (v) in a three-electrode arrangement. The static test is advantageous due to its low demands on material and instrumental equipment. The dynamic test allows for the testing of corrosion rates of metallic materials at more severe conditions. The static test with a reflux cooler allows for the testing in environments with higher viscosity (e.g., engine oils) at higher temperatures in the presence of oxidation or an inert atmosphere. The electrochemical measurements provide a more comprehensive view on corrosion processes. The presented cell geometries and arrangements (the two-electrode and three-electrode systems) make it possible to perform measurements in biofuel environments without base electrolytes that could have a negative impact on the results and load them with measurement errors. The presented methods make it possible to study the corrosion aggressiveness of an environment, the corrosion resistance of metallic materials, and the efficiency of corrosion inhibitors with representative and reproducible results. The results obtained using these methods can help to understand corrosion processes in more detail to minimize the damages caused by corrosion.

The testing of processes associated with material corrosion can often be difficult especially in non-aqueous environments. Here, we present different methods for short-term and long-term testing of corrosion behavior of non-aqueous environments such as biofuels, especially those containing bioethanol.

金属腐蚀与腐蚀抑制剂在低导电介质中的效率

Material corrosion can be a limiting factor for different materials in many applications. Thus, it is necessary to better understand corrosion processes, ...

科研

环境科学

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation

Electrochemical impedance spectroscopy (EIS) was used for advanced characterization of organic electroactive compounds along with cyclic voltammetry (CV). In the case of fast reversible electrochemical processes, current is predominantly affected by the rate of diffusion, which is the slowest and limiting stage. EIS is a powerful technique that allows separate analysis of stages of charge transfer that have different AC frequency response. The capability of the method was used to extract the value of charge transfer resistance, which characterizes the rate of charge exchange on the electrode-solution interface. The application of this technique is broad, from biochemistry up to organic electronics. In this work, we are presenting the method of analysis of organic compounds for optoelectronic applications.

Electrochemical impedance spectroscopy (EIS) of species that undergo reversible oxidation or reduction in solution was used for determination of rate constants of oxidation or reduction.

电化学阻抗谱作为电化学速率常数估计的一种工具

Electrochemical impedance spectroscopy (EIS) was used for advanced characterization of organic electroactive compounds along with cyclic voltammetry (CV). ...

化学

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds

Cyclic voltammetry (CV) is a technique used in the analysis of organic compounds. When this technique is combined with electron paramagnetic resonance (EPR) or ultraviolet-visible and near-infrared (UV-Vis-NIR) spectroscopies, we obtain useful information such as electron affinity, ionization potential, band-gap energies, the type of charge carriers, and degradation information that can be used to synthesize stable organic electronic devices. In this study, we present electrochemical and spectroelectrochemical methods to analyze the processes occurring in active layers of an organic device as well as the generated charge carriers.

In this article, we describe electrochemical, electron paramagnetic resonance, and ultraviolet-visible and near-infrared spectroelectrochemical methods to analyze organic compounds for application in organic electronics.

利用循环伏安法、紫外-近红外光谱和 EPR 光谱电化学对有机化合物进行分析

Cyclic voltammetry (CV) is a technique used in the analysis of organic compounds. When this technique is combined with electron paramagnetic resonance ...

Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen reduction reaction. Spontaneous galvanic displacement was used to deposit Pt layers onto Ni nanowire substrates. The synthesis approach produced catalysts with high specific activities and high Pt surface areas. Hydrogen annealing improved Pt and Ni mixing and specific activity. Acid leaching was used to preferentially remove Ni near the nanowire surface, and oxygen annealing was used to stabilize near-surface Ni, improving durability and minimizing Ni dissolution. These protocols detail the optimization of each post-synthesis processing step, including hydrogen annealing to 250 &#176;C, exposure to 0.1 M nitric acid, and oxygen annealing to 175 &#176;C. Through these steps, Pt-Ni nanowires produced increased activities more than an order of magnitude than Pt nanoparticles, while offering significant durability improvements. The presented protocols are based on Pt-Ni systems in the development of fuel cell catalysts. These techniques have also been used for a variety of metal combinations, and can be applied to develop catalysts for a number of electrochemical processes.

&#160; The protocol describes the synthesis and electrochemical testing of platinum-nickel nanowires. Nanowires were synthesized by the galvanic displacement of a nickel nanowire template. Post-synthesis processing, including hydrogen annealing, acid leaching, and oxygen annealing were used to optimize nanowire performance and durability in the oxygen reduction reaction.

铂镍纳米线的合成及减氧性能优化

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen ...

Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures

The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these structures. Corrosion of the embedded reinforcing steel is the most frequent cause for degradation. While it is well known that the ability of a structure to withstand corrosion depends strongly on factors such as the materials used or the age, it is common practice to rely on threshold values stipulated in standards or textbooks. These threshold values for corrosion initiation (Ccrit) are independent of the actual properties of a certain structure, which clearly limits the accuracy of condition assessments and service life predictions. The practice of using tabulated values can be traced to the lack of reliable methods to determine Ccrit on-site and in the laboratory.
Here, an experimental protocol to determine Ccrit for individual engineering structures or structural members is presented. A number of reinforced concrete samples are taken from structures and laboratory corrosion testing is performed. The main advantage of this method is that it ensures real conditions concerning parameters that are well known to greatly influence Ccrit, such as the steel-concrete interface, which cannot be representatively mimicked in laboratory-produced samples. At the same time, the accelerated corrosion test in the laboratory permits the reliable determination of Ccrit prior to corrosion initiation on the tested structure; this is a major advantage over all common condition assessment methods that only permit estimating the conditions for corrosion after initiation, i.e., when the structure is already damaged.
The protocol yields the statistical distribution of Ccrit for the tested structure. This serves as a basis for probabilistic prediction models for the remaining time to corrosion, which is needed for maintenance planning. This method can potentially be used in material testing of civil infrastructures, similar to established methods used for mechanical testing.

We propose a method to measure a parameter that is highly relevant for corrosion assessments or predictions of reinforced concrete structures, with the main advantage of permitting testing of samples from engineering structures. This ensures real conditions at the steel-concrete interface, which are crucial to avoid artifacts of laboratory-made samples.

测定钢筋混凝土结构试样腐蚀的氯化物阈值的试验规程

The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these ...

工程学

Determination of Thermodynamic Properties of Alkaline Earth-liquid Metal Alloys Using the Electromotive Force Technique

A novel electrochemical cell based on a CaF2 solid-state electrolyte has been developed to measure the electromotive force (emf) of binary alkaline earth-liquid metal alloys as functions of both composition and temperature in order to acquire thermodynamic data. The cell consists of a chemically stable solid-state CaF2-AF2 electrolyte (where A is the alkaline-earth element such as Ca, Sr, or Ba), with binary A-B alloy (where B is the liquid metal such as Bi or Sb) working electrodes, and a pure A metal reference electrode. Emf data are collected over a temperature range of 723 K to 1,123 K in 25 K increments for multiple alloy compositions per experiment and the results are analyzed to yield activity values, phase transition temperatures, and partial molar entropies/enthalpies for each composition.

This protocol describes the measurement of the electromotive force of alkaline-earth elements in liquid metal alloys at high temperatures (723-1,123 K) to determine their thermodynamic properties, including activity, partial molar entropy, partial molar enthalpy, and phase transition temperatures, over a wide composition range.

用电动势技术测定碱土金属合金的热力学性质

A novel electrochemical cell based on a CaF2 solid-state electrolyte has been developed to measure the electromotive force (emf) of binary alkaline ...

Determining Tribocorrosion Rate and Wear-Corrosion Synergy of Bulk and Thin Film Aluminum Alloys

The increasing complexity and severity of service conditions in areas, such as aerospace and marine industries, nuclear systems, microelectronics, batteries, and biomedical devices, etc., impose great challenges on the reliable performance of alloys exposed to extreme conditions where mechanical and electrochemical attack co-exist. Finding ways for alloys to mitigate the combined attack of wear and corrosion (i.e., tribocorrosion) under such extreme conditions is thus highly critical for improving their reliability and service lifetime when used in such conditions. The challenge lies in the fact that wear and corrosion are not independent of each other, but rather work synergistically to accelerate the total material loss. Thus, a reliable method to evaluate the tribocorrosion resistance of metals and alloys is needed. Here, a protocol for measuring the tribocorrosion rate and wear-corrosion synergy of Al-based bulk and thin film samples in a corrosive environment under room temperature is presented.

Here, we present a protocol to measure the tribocorrosion rate and wear-corrosion synergy of thin film and bulk Al alloys in simulated sea water at room temperature.

Tribocorrosion 和薄膜铝合金的磨损与腐蚀协同性测定

The increasing complexity and severity of service conditions in areas, such as aerospace and marine industries, nuclear systems, microelectronics, ...

Electrochemical Roughening of Thin-Film Platinum Macro and Microelectrodes

This protocol demonstrates a method for electrochemical roughening of thin-film platinum electrodes without preferential dissolution at grain boundaries of the metal. Using this method, a crack free, thin-film macroelectrode surface with up to 40 times increase in active surface area was obtained. The roughening is easy to do in a standard electrochemical characterization laboratory and incudes the application of voltage pulses followed by extended application of a reductive voltage in a perchloric acid solution. The protocol includes the chemical and electrochemical preparation of both a macroscale (1.2 mm diameter) and microscale (20 &#181;m diameter) platinum disc electrode surface, roughening the electrode surface and characterizing the effects of surface roughening on electrode active surface area. This electrochemical characterization includes cyclic voltammetry and impedance spectroscopy and is demonstrated for both the macroelectrodes and the microelectrodes. Roughening increases electrode active surface area, decreases electrode impedance, increases platinum charge injection limits to those of titanium nitride electrodes of same geometry and improves substrates for adhesion of electrochemically deposited films.

This protocol demonstrates a method for electrochemical roughening of thin-film platinum electrodes without preferential dissolution at grain boundaries. The electrochemical techniques of cyclic voltammetry and impedance spectroscopy are demonstrated to characterize these electrode surfaces.

薄膜铂金宏观和微电极的电化学粗加工

This protocol demonstrates a method for electrochemical roughening of thin-film platinum electrodes without preferential dissolution at grain boundaries ...

Applying Dynamic Strain on Thin Oxide Films Immobilized on a Pseudoelastic Nickel-Titanium Alloy

Direct alteration of material structure/function through strain is a growing area of research that has allowed for novel properties of materials to emerge. Tuning material structure can be achieved by controlling an external force imposed on materials and inducing stress-strain responses (i.e., applying dynamic strain). Electroactive thin films are typically deposited on shape or volume tunable elastic substrates, where mechanical loading (i.e., compression or tension) can affect film structure and function through imposed strain. Here, we summarize methods for straining n-type doped titanium dioxide (TiO2) films prepared by a thermal treatment of a pseudo-elastic nickel-titanium alloy (Nitinol). The main purpose of the described methods is to study how strain affects electrocatalytic activities of metal oxide, specifically hydrogen evolution and oxygen evolution reactions. The same system can be adapted to study the effect of strain more broadly. Strain engineering can be applied for optimization of a material function, as well as for design of adjustable, multifunctional (photo)electrocatalytic materials under external stress control.

Dynamic, tensile strain is applied on TiO2 thin films to study the effects of strain on electrocatalysis, specifically proton reduction and water oxidation. TiO2 films are prepared by thermal treatment of the pseudo-elastic NiTi alloy (Nitinol).

将动态应变应用于固定在伪弹性镍钛合金上的薄氧化物薄膜

Direct alteration of material structure/function through strain is a growing area of research that has allowed for novel properties of materials to ...

Electrochemical Measurements of Supported Catalysts Using a Potentiostat/Galvanostat

Source: Laboratory of Dr. Yuriy Rom&#225;n &#8212; Massachusetts Institute of Technology
A potentiostat/galvanostat (often referred to as simply a potentiostat) is an instrument that measures current at an applied potential (potentiostatic operation) or measures potential at an applied current (galvanostatic operation) (Figure 1). It is the most commonly used instrument in the electrochemical characterization of anode and cathode materials for fuel cells, electrolyzers, batteries, and supercapacitors.
Conventionally, these anode and cathode materials are interfaced with a potentiostat via a three-electrode electrochemical cell. The electrode leads from the potentiostat are connected to the reference electrode, the counter electrode (often called the auxiliary electrode), and the working electrode (which contains the test material of interest). The electrochemical cell is then filled with a high ionic strength electrolyte solution, such as an acidic, alkaline, or salt solution. The media for this high ionic strength solution is typically aqueous; however, for applications necessitating higher operating cell potential windows, such as batteries and supercapacitors, non-aqueous media is often used. The cell media is degassed with an inert gas (to prevent unwanted side reactions) or with a test gas (if the test reaction involves a gas at one of the electrodes).
Alternatively, a salt bridge or membrane is employed to maintain ionic contact if the two half cells are to be measured in different electrolytes. In heterogeneous electrocatalysis, this type of &#34;two compartment&#34; cell is often used if the test molecule at the working electrode is also reactive at the counterelectrode. This happens frequently as the counterelectrode typically employed is platinum, which is a highly active catalyst for many reactions. Here, single compartment cells will be used, where all three electrodes are in the same media.
This video will explain the process of polishing a working electrode, preparing a catalyst ink, mounting the catalyst ink onto the working electrode, preparing the electrochemical cell, and then performing electrochemical measurements. The measurements that are performed include: cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronopotentiometry (CP), and chronoamperometry (CA).
<img alt="Figure 1" src="/files/ftp_upload/5698/5698fig1.jpg" /> 
Figure 1. An example of a single compartment electrochemical cell. a.) Teflon cap, b.) glass cell, c.) Pt wire counter electrode, d.) working electrode, e.) Ag/AgCl reference electrode, f.) 0.5 M aqueous sulfuric acid electrolyte solution.