Electrochemical Microcell Research Articles

Spatially Confined Microcells: A Path toward TMD Catalyst Design.

With the ability to maximize the exposure of nearly all active sites to reactions, two-dimensional transition metal dichalcogenide (TMD) has become a fascinating new class of materials for electrocatalysis. Recently, electrochemical microcells have been developed, and their unique spatial-confined capability enables understanding of catalytic behaviors at a single material level, significantly promoting this field. This Review provides an overview of the recent progress in microcell-based TMD electrocatalyst studies. We first introduced the structural characteristics of TMD materials and discussed their site engineering strategies for electrocatalysis. Later, we comprehensively described two distinct types of microcells: the window-confined on-chip electrochemical microcell (OCEM) and the droplet-confined scanning electrochemical cell microscopy (SECCM). Their setups, working principles, and instrumentation were elucidated in detail, respectively. Furthermore, we summarized recent advances of OCEM and SECCM obtained in TMD catalysts, such as active site identification and imaging, site monitoring, modulation of charge injection and transport, and electrostatic field gating. Finally, we discussed the current challenges and provided personal perspectives on electrochemical microcell research.

Portable Device for Potentiometric Determination of Antioxidant Capacity.

For the first time, a prototype of a portable device for the potentiometric determination of antioxidant capacity based on a new measurement principle is proposed. A feature of the approach is the use of an electrochemical microcell with separated spaces and two identical electrodes with immobilized reagents. An antioxidant solution is introduced into one half-cell, and the antioxidants interact with the reagents. The other half-cell contains only reagents. The potential difference between the electrodes is due to the change in the ratio of the oxidized and reduced form of the reagents, which occurs as a result of the reaction with the antioxidants in one of the half-cells and is related to their concentration. The range of linearity of the microcell with immobilized reagents is 40-4000 μM-eq, and the limit of detection is 20 μM-eq. The device was successfully tested in the analysis of standard antioxidant solutions. The recoveries were (92-113)%, and the relative standard deviation did not exceed 15%. A good correlation was found between the data obtained by the approach and the potentiometric method in a macrocell for fruit juice analysis. Pearson's coefficient for the obtained experimental data was 0.9955. The proposed portable device is promising and can be used in field conditions.

Design of a Boron-Doped Diamond Microcell Grafted with HRP for the Sensitive and Selective Detection of Ochratoxin A

Ochratoxin A (OTA) is considered the most toxic member of the ochratoxin group. Herein, a novel label-free electrochemical sensor based on the horseradish peroxidase (HRP) enzyme is developed for OTA detection. The HRP enzyme was covalently immobilized on the working electrode of a planar boron-doped diamond (BDD) electrochemical microcell previously covered with diazonium film and grafted with single-walled carbon nanotubes (SWCNTs). Each surface modification step was evaluated by cyclic voltammetry and scanning electron microscopy. Square wave voltammetry was used for the detection of OTA. The linear working range of the biosensors ranged between 10−14 and 0.1 M, with a limit of detection (LOD) of 10 fM, an RSD equal to 5%, and a sensitivity of 0.8 µA per decade. In addition, the sensor showed good selectivity in the presence of OTA analogs; it was validated in samples such as corn, feed, and wheat. The metrological performance of the present sensor makes it a good alternative for OTA detection.

Electrochemical Characteristics of Intermetallic Phases in Al–Cu–Li Alloys

This study provides a comprehensive overview of the electrochemical characteristics of intermetallic compounds (IMCs) commonly encountered in the 3rd generation Al–Cu–Li alloys. The electrochemical measurements were carried out on a AA2070-T8 alloy and surrogate alloys that have the compositions of select IMCs, typically found in AA2070-T8. The effects of environmental variables such as [Cl−] and pH on the corrosion potential, pitting potential, repassivation potential, corrosion rate, and galvanic current of these IMCs were thoroughly evaluated utilizing the electrochemical microcell method. An electrochemical database was documented that covers eight groups of common IMCs in various Al alloys. The findings improve the understanding of interactions between matrix and IMCs in Al alloys, with implications for corrosion mitigation and new materials design.

Iontronic memories based on ionic redox systems: operation protocols.

A recently developed, new ionic device called the ionic voltage effect soft triode (IVEST) was optimized, tuned and embedded into a memory application concept. The device is an electrochemical micro-cell, consisting of a top electrode and two bottom electrodes. The device controls the concentration and diffusion of ions via the voltage applied on the top electrode. The device showed a memory effect lasting up to 6 hours. Despite the remarkably large stability time, the memory contrast was small in the first device versions. Now, we have increased the memory contrast by introducing a new external electrical circuit layout combined with a new operation protocol. This new investigation also reveals peculiarities of the memory and shows that the IVEST can be used in memory applications. These iontronic memories show a secondary information storage connected with the read-out frequency.

1T’ RexMo1−xS2–2H MoS2 Lateral Heterojunction for Enhanced Hydrogen Evolution Reaction Performance

AbstractThe imperfect interfaces between 2D transition metal dichalcogenides (TMDs) are suitable for boosting the hydrogen evolution reaction (HER) during water electrolysis. Here, the improved catalytic activity at the spatial heterojunction between 1T’ RexMo1−xS2 and 2H MoS2 is reported. Atomic‐scale electron microscopy confirms that the heterojunction is constructed by an in‐situ two‐step growth process through chemical vapor deposition. Electrochemical microcell measurements demonstrate that the 1T’ RexMo1−xS2–2H MoS2 lateral heterojunction exhibits the best HER catalytic performance among all TMD catalysts with an overpotential of ≈84 mV at 10 mA cm−2 current density and 58 mV dec−1 Tafel slope. Kelvin probe force microscopy shows ≈40 meV as the work function difference between 2H MoS2 and 1T’ RexMo1−xS2, facilitating the electron transfer from 2H MoS2 to 1T’ RexMo1−xS2 at the heterojunction. First‐principles calculations reveal that Mo‐rich heterojunctions with high structural stability are formed, and the HER performance is improved with the combination of increased density of states near the Fermi level and optimal ΔGH* as low as 0.07 eV. Those synergetic effects with many electrons and active sites with optimal ΔGH* improve HER performance at the heterojunction. These results provide new insights into understanding the role of the heterojunction for HER.

On-site weld quality assessment and qualification for stainless steels tanks

Stainless steel tanks are frequently degraded by localized corrosion in bioprocess industries. A case study of 2101 duplex stainless steel tank allowed to apply a portable electrochemical microcell system (PassivityScan) for on-site weld inspection and corrosion monitoring from the manufacturing until 12 months of operation. During the tank manufacturing, the double loop electrochemical potentiokinetic reactivation technique was applied to measure the sensitization degree on the welded regions. The manufactured tank was submitted to the passivation treatment to improve the passivation properties and corrosion resistance. On-site cyclic polarization tests were performed and confirmed the increase of passivation level of treated surface. The passivation level was measured again after 12�months of operation and detected a lower passivation level compared to the initial passivated surface, indicating that the passivation treatment lost its effect after that period. Therefore, an acceptance criterion to passivation level was empirically determined. PassivityScan is an advanced device to qualify the welds and the passivated surfaces, and useful for corrosion monitoring and the reliability maintenance.

A novel self-assembled gold nanoparticles-molecularly imprinted modified carbon ionic liquid electrode with high sensitivity and selectivity for the rapid determination of bisphenol A leached from plastic containers

In the present work, a new nanocomposite, reduced graphene oxide (rGO) decorated by mercaptamine- gold nanoparticles (AuNPs-MCA-rGO) was synthesized for the first time by a facile hydrothermal method. The carbon ionic liquid electrode (CILE) was modified by AuNPs-MCA-rGO and molecular imprinted polymer (MIP) to sensitive and selective electrochemical microanalysis of bisphenol A (BPA). The modifier provides a large surface area, selective sites and exhibited a rapid electron transport rate for the bisphenol A (BPA). In this research, a new electrochemical microcell with a volume of 25 µL was fabricated which can reduce drastically the required volume of analysis. This advantage leads to less use of chemicals and the possibility of micro sample analyzing. Therefore, the method is presented as a economical electro-analytical method. Under the optimized conditions, the linear response was observed for BPA concentration in the range of 4.0 × 10−9 to 1.8 × 10−5 M by cyclic voltammetry (CV). The detection limit of the method was obtained as 1.1 × 10−9 M by CV. Because of imprinted polymers in composition of modifier, the proposed sensor shows great potential applications in biomarker detection, food safety testing and environmental monitoring. It was used for the quantitative determination of BPA leached from plastic containers for food storage (PVC food package, PC baby bottle, and PC water bottle).

Corrosion Behavior and Microstructural Characterization of Friction Stir Welded API X70 Steel

Friction stir welding (FSW) is an excellent alternative process used in pipelines circumferential welds due to fusion welded joint low corrosion resistance. This study describes the corrosion resistance as a function of the microstructural features resulting from an API X70 FSW welded joint. The microstructural features were examined by optical microscopy, scanning electron microscopy, and x-ray diffraction. The corrosion analysis was conducted employing potentiodynamic polarization tests using an electrochemical microcell, which allowed to test small circular areas delimited by a 2 mm in diameter O-ring gasket. The base metal and heat-affected zone were the most susceptible regions to corrosion due to their banded microstructures. The re-stirred-zone and stir zone were the most resistant regions to corrosion which was associated to grain refinement. The corrosion rate presented by the base metal and the heat-affected zone was approximately six times higher than the region of least susceptibility to corrosion, in this case, the re-stirred-zone.

3D-printed fluidic electrochemical microcell for sequential injection/stripping analysis of heavy metals

In this paper, a 3D-printed microfluidic device is described which is suitable for sequential injection/anodic stripping voltammetric (SIA-ASV) determination of Pb(II) and Cd(II). The fluidic device is manufactured by 3D-printing in a single-step using a dual extruder 3D printer. The device is composed of a microfluidic cell (printed from a non-conductive polylactic acid (PLA) filament) and of 3 electrodes (printed from a conductive carbon-loaded PLA filament) which are integrated within the fluidic cell. During the preconcentration step, a zone of the sample (containing the target cations) and a zone of Bi(III) solution are mixed on-line and the cations are reduced on the working electrode forming a bismuth alloy. The detection step involves a voltametric scan in static solution, in which the accumulated metals are oxidized while the oxidation current is monitored. After the optimization of the relevant parameters, the limit of detection is 0.38 μg L−1 for Pb(II) and 0.57 μg L−1 for Cd(II), while the within-device repeatability and the between-device reproducibility are lower than 4.5% (n = 8) and 9% (n = 6), respectively, for both cations at the 30 μg L−1 level. The device was successfully applied to the simultaneous determination of Pb(II) and Cd(II) in a honey sample.

(Invited) Innovative 3D-Printed Flow-Type Electrochemical Microcell for Ultra-High Spatial Resolution Electrochemistry

Advances in 3D-printing technology have been used to design and develop a customizable flow-type electrochemical microcell that provides analytical resolution comparable to that of conventional glass capillary-based electrochemical microcells. In addition to being highly reproducible compared to the fabrication of glass capillaries, the advantages of this design are increased durability, decreased production costs, and better control over design parameters while maintaining ultra-high spatial resolution. The design is a three-component microcell that combines 3D printing with conventional machining to allow rapid prototyping and testing of flow designs and apertures sizes while maintaining a consistent foundation upon which the design can be built. The key benefit of the three-component design is the ability to replace parts as needed without complete disassembly. The design and application of two classes of flow-type electrochemical microcell, high-resolution (~100 µm spot size) and ultra-high resolution (~10 µm spot size), will be presented. Additionally, the proposed prototype introduces the practicality of a six-axis robot arm for positioning the microcell and is advantageous over a conventional three-axis gantry system allowing for the analysis of irregular sample geometries. The microcell prototype was tested and evaluated to demonstrate repeatability in use, accuracy in spatial resolution and experimental results, and capability in the analysis of various materials and surface finishes. The ease of use and endurance of the design is also demonstrated through repeated use. This microcell has the potential for applications in corrosion, electrodeposition, and electroanalysis, amongst others.Acknowledgements: This work was supported by the United States Nuclear Regulatory Commission (NRC) under contract NRC-HQ-84-16-G-0033. Ms. Nancy Hebron-Israel serves as the program manager.

Investigation into Local Electrochemical Behavior of Metals with 3D Printed Solution Flow-Type Micro Droplet Cell

In recent years, metallic materials have shown to exhibit advanced properties, such as high strength, high corrosion resistance and flatness. Non-uniformity of metallic materials plays an significant role in these properties. In order to investigate the non-uniformity of metals, it is necessary to carry out a higher resolution analysis. Therefore, electrochemical technology in small area is required. One of the techniques is an electrochemical microdroplet cell. The electrochemical micro-cell has received attention as a measurement method to investigate local electrochemical behaviors. There are tow types of electrochemical microdroplet cells; a meniscus type and a gasket type. The classification is based on the difference in the structure between the capillary tip and sample surface.1),2) Independent of structure of the cell, the microdroplet cells have enabled us to investigate small surface areas. However, because of a concentration gradient in the solution inside the capillary, appropriate measurement and chemical reaction cannot be performed. To avoid this problem, a gasket-type electrochemical microdroplet cell with a θ-shaped glass capillary was developed.3) Solution supply and ejection could be performed using two channels. A dual capillary solution flow-type microdroplet cell (Sf-MDC) was also developed.4) This Sf-MDC has a co-axial double tube structure which has two capillaries with different diameters; the solution is supplied from the inner capillary and collected by the outer capillary. This Sf-MDC was applied to form porous-type aluminum anodic oxide locally5)-7) and to investigate SCC mechanism near fusion line.8) This Sf-MDC is very useful for local electrochemical measurement and mask-less local surface treatments. However, the structures of previous Sf-MDC are very complex and difficult to fabricate. Therefore, 3D printing was applied to fabricate Sf-MDC and local electrochemical measurements were carried out by fabricated Sf-MDC. Sf-MDC was designed using computer-aided design software and fabricated by 3D printer. A Pt wire and an Ag / AgCl wire were inserted inside the cell as counter and reference electrodes. Fig. 1 shows the 3D printed Sf-MDC is attached to a microscope. Using optical microscope, it is possible to control measuring position precisely and carry out electrochemical measurement locally. The surface states before and after the electrochemical measurements were observed. The immersion potential measurements and the potentio-dynamic polarization measurements were carried out using 10 mM NaCl. Both the immersion potentials and the polarization curves of aluminum alloys were different by measuring locations.References1) M. M. Lohrengel, C. Rosenkranz, I. Klüppel, A. Moehring, B. Van den Bossche, J. Deconinck; Electrochim. Acta, 49, 2863 (2004).2) H. Böhni, T.Suter, and A. Schreyer; Electrohim. Acta, 10, 1361 (1995).3) M. M. Lohrengel, I. Klüppel, C. Rosenkranz, H. Bettermann, and J. W. Schultze; Electrochim. Acta, 48, 3203 (2003).4) K. Fushimi, S. Yamamoto, R. Ozaki and H. Habasaki; Electrochem. Acta, 53, 2529 (2008).5) M. Sakairi, T. Yamaguchi, T. Murata and K. Fushimi; ECS Trans., 50, 255 (2013).6) M. Sakairi, F. Nishino and R. Itzinger; Surf. Interface Anal., 48, 921 (2015).7) T. Murata, Y. Goto, M. Sakairi, K. Fushimi and T. Kiukuchi; ECS Trans., 33, 57 (2011).8) S. Hashizume, T. Nakayama, M. Sakairi and K. Fushimi; Zairyo-to-Kankyo, 60, 196 (2011).Fig. 1 Optical images of local electrochemical measurement by Sf-MDC fabricated by 3D printer. Figure 1

Multi-physical analysis of the electrochemical behaviour of OFHC copper surfaces obtained by orthogonal cutting

ABSTRACT As mechanical, physical and microstructural properties of metals can be significantly affected by the machining process, electrochemical properties and corrosion resistance are consequently altered. Manufacturers should control the impact of cutting conditions on surface integrity, as it will affect the component’s functional performance and life. This study addresses the case of orthogonal cutting of oxygen-free high conductivity copper. A set of experiments was performed and a statistical analysis was conducted to reveal the relationship between the cutting conditions and the surface integrity in terms of residual stresses, microstructure, plastic deformation and hardness and the impact of those parameters on the electrochemical behaviour. The physical origins of the observed phenomena are explained. The results show that the surface performance can be controlled by selecting the appropriate cutting conditions (e.g. reducing the tensile residual stress and roughness by more than 75%), such that the electrochemical behaviour can be enhanced. Highlights Performing orthogonal cutting tests varying cutting conditions on oxygen-free high conductivity (OFHC) copper. Analyzing mechanical and microstructural state of OFHC copper machined surfaces including roughness, residual stresses, grain size and dislocation density. Analyzing the electrochemical behaviour of the machined surfaces using polarisation curves issued from electrochemical microcell tests. Relating surface integrity mechanical and microstructural properties to electrochemical properties using statistical analysis. Optimising cutting conditions to control the surface integrity state and then ameliorate the corrosion resistance.

Retractable-pen-based renewable silver amalgam film electrode for microliter sample analysis of electrochemically reducible environmental pollutants

A novel, inexpensive, and simple construction of a retractable-pen-based renewable silver amalgam film electrode (RAE) was introduced in this study for electrochemical sensing of electrochemically reducible compounds in small sample volumes. This electrode is based on a mechanical renewal of the amalgam film achieved by using mechanisms found in a common retractable ballpoint pen. Cadmium(II) and two model environmental pollutants (4-nitrophenol (NP) and 3-nitrobiphenyl (NB)) were used to evaluate the performance of the novel RAE and its utilization in the electrochemical microcell. In order to decrease the high variability of observed reduction potentials of NP and NB on RAE, the influence of the content of silver in the amalgam used for the renewal of the film was investigated. It was found that 4 % of Ag in the amalgam improved the repeatability of peak potentials. Obtained limit of quantification (LOQ) for Cd(II) was 54 nmol L–1 (6.1 ppb) in acetate buffer (pH 4.8); LOQ for NP was 1.2 μmol L–1 in Briton-Robinson (BR) buffer (pH 4.0). LOQ for NB was 2.5 μmol L–1 in BR buffer (pH 6.0) – methanol (8:2, v/v) medium. The possibility of further decrease of LOQ of NB to a nanomolar range with the help of the microcell was demonstrated by the liquid-liquid extraction (LLE) to hexane with the preconcentration factor of 1000. Moreover, RAE offers portability, long-term stability, simple renewal of the surface, a wide cathodic potential window, and it can be considered as an inexpensive, robust, and safe alternative to other mercury-based electrochemical sensors.

Effects of dynamic recrystallization and strain-induced dynamic precipitation on the corrosion behavior of partially recrystallized Mg–9Al–1Zn alloys

Abstract The corrosion susceptibility of recrystallized and un-recrystallized grains in equal channel angular pressed (ECAPed) Mg–9Al–1Zn (AZ91) alloys immersed in chloride containing media was investigated through immersion testing and an electrochemical microcell technique coupled with high resolution techniques such as scanning Kelvin probe force microscopy (SKPFM), transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD). During ECAP, dynamic recrystallization (DRX) and strain-induced dynamic precipitation (SIDP) simultaneously occurred, resulting in a bimodal grain structure of original elongated coarse grains and newly formed equiaxed fine grains with a large volume fraction of β-Mg17Al12 precipitates. Corrosion preferentially initiates and propagates in the DRXed grains, owing to the greater microchemistry difference between the β-Mg17Al12 precipitates formed at the DRXed grain boundaries and the adjacent α-Mg matrix, which induces a strong microgalvanic coupling between these phases. Additionally, the weaker basal texture of the DRXed grains also makes these grains more susceptible to electrochemical reactions than the highly textured un-DRXed grains. The influence of dynamic recrystallization and dynamic precipitation was also studied in ECAPed alloys with different levels of deformation strain through corrosion and electrochemical techniques. Increasing the strain level led to a more uniform corrosion with a shallow penetration depth, lower corrosion rate values, and higher protective ability of the oxide film. Furthermore, higher levels of strain resulted in greater hardness values of the ECAPed alloys. The superior corrosion resistance and strength of the ECAPed alloys with increasing strain level was attributed to the combination of smaller DRXed grain size, higher DRX ratio, and higher volume fraction of uniformly distributed fine β-Mg17Al12 precipitates.

Effect of MAG welding transfer mode on sigma phase precipitation and corrosion performance of 316L stainless steel multi-pass welds

The effect of multi-pass MAG welding transfer modes on the sigma phase precipitation and corrosion performance of AISI 316L thick plate were investigated. The evolution of the microstructure was examined by optical and electron microscopy as well as ferritscope measurements and energy dispersive X-ray spectrometry. An electrochemical microcell was then used to characterize the electrochemical behaviour of the different weld regions. The fusion line was the most critical zone for pitting corrosion for all welding procedures, due to the sigma phase precipitation, alloy elements partitioning and galvanic coupling between base metal and weld metal. It was observed the formation of sigma phase after short-circuiting or spray-arc modes, with no evidence of it to the pulsed-arc, which obtained the best corrosion resistance performance. The results evidenced the selective corrosion around sigma phase due to the depletion in Cr and Mo, with subsequent pitting nucleation. A strong correlation between the MAG welding transfer modes and the sigma phase morphology was observed. The influence of weld parameters on microstructure evolution and corrosion resistance performance was discussed. The corrosion resistance performance of the MAG welding procedures was ranked as: pulsed-arc > short-circuit > spray-arc.

New insights on the corrosion mechanism of a peak-aged Mg–9Al–1Zn alloy in a chloride environment

It has been documented that the corrosion behavior of AZ91 (Mg–9Al–1Zn, wt.%) alloy is strongly influenced by the morphology, distribution, and volume fraction of secondary phases, however, the proposed corrosion mechanisms are questioned due to new experimental findings. The present study focused on providing a more detailed understanding of the corrosion mechanism of a peak-aged AZ91 alloy exposed to a chloride environment by using scanning Kelvin probe force microscopy, immersion testing, optical microscopy, scanning and transmission electron microscopy techniques and electrochemical microcell technique. It was found that corrosion was simultaneously initiated in the interior of α-Mg grains and in the local α-Mg phase within the α + β lamellar precipitate; furthermore, the lamellar precipitate/α-Mg matrix boundary acted as a barrier for corrosion propagation. The proposed corrosion initiation mechanism is opposed to previous investigations reporting the development of micro-galvanic coupling between the β-Mg17Al12 phase and the adjacent α-Mg matrix, which cannot be supported by our experimental findings. The corrosion propagation in the peak-aged alloy was dominated by the preferential anodic dissolution at the interior of the α-Mg matrix due to its faster corrosion reaction kinetics compared to the micro-galvanic corrosion process between the β-phase and the local α-Mg phase occurring inside the lamellar precipitate.

Communication—Design, Development, and Evaluation of a High Resolution, Customizable 3D-Printed Flow-Type Electrochemical Microcell

Advances in 3D-printing technology was used to design and develop a customizable flow-type electrochemical microcell with analytical resolution similar to conventional glass capillary-based microcells. The advantages of this design are better and easier reproducibility, increased durability, and better control over design parameters. 3D printing was combined with conventional machining to enable rapid prototyping and testing of various flow designs and apertures sizes. Results from potentiodynamic polarization of copper demonstrated repeatability and accuracy in spatial resolution. Reproducibility of experimental area had 1.9% variation between different spots. The ease of use and endurance of the design was demonstrated through repeated use.

Reversing Interfacial Catalysis of Ambipolar WSe2 Single Crystal.

An improved understanding of the origin of the electrocatalytic activity is of importance to the rational design of highly efficient electrocatalysts for the hydrogen evolution reaction. Here, an ambipolar single‐crystal tungsten diselenide (WSe2) semiconductor is employed as a model system where the conductance and carrier of WSe2 can be individually tuned by external electric fields. The field‐tuned electrochemical microcell is fabricated based on the single‐crystal WSe2 and the catalytic activity of the WSe2 microcell is measured versus the external electric field. Results show that WSe2 with electrons serving as the dominant carrier yields much higher activity than WSe2 with holes serving as the dominant carrier even both systems exhibit similar conductance. The catalytic activity enhancement can be characterized by the Tafel slope decrease from 138 to 104 mV per decade, while the electron area concentration increases from 0.64 × 1012 to 1.72 × 1012 cm−2. To further understand the underlying mechanism, the Gibbs free energy and charge distribution for adsorbed hydrogen on WSe2 versus the area charge concentration is systematically computed, which is in line with experiments. This comprehensive study not only sheds light on the mechanism underlying the electrocatalysis processes, but also offers a strategy to achieve higher electrocatalytic activity.

On the Development of a Flow-Type Electrochemical Microcell

Localized corrosion is one of the most challenging and important fields in corrosion science. While there are a number of methods for studying corrosion at small scales, a majority of these methods involves immersion of a sample into an environment of interest, exposing them for prescribed amount of time, and then analyzing the sample’s surface post-exposure. Methods that have been studied include (i) the use of electrochemical techniques during immersion to understand transient processes that initiate and those that propagate localized corrosion behavior such as scanning reference electrode technique (SRET), and (ii) using electrochemical microcells or scanning droplet cells to perform electrochemical analysis of sample surfaces without the need to immerse an entire sample into an environment. The downside of these techniques is either that the entire sample must be sacrificed for the analysis or that the analysis area is still too large to truly isolate localized corrosion processes. In this study, we demonstrate a novel approach to the development of a flow-type electrochemical microcell that provides the necessary resolution to study localized corrosion while being completely customizable. Additionally, results on various samples will be presented showing the applicability of the system as well as verification of performance. Acknowledgement: This work was performed under the auspices of the US Nuclear Regulatory Commission (NRC) under contract NRC-HQ-84-16-G-0033. Ms. Nancy Hebron-Isreal serves as the program manager.