Electrochemical Workstation Research Articles

Study on microstructure and electrochemical corrosion behavior of ζ-FeZn13 phase layer in hot-dip galvanized coating

In this study, the electrochemical corrosion behavior of outburst and flat ζ-FeZn13 phase layers was investigated using scanning electron microscopy, field emission scanning electron microscopy, electrochemical workstation, and Raman spectroscopy instrument. The ζ phase layer is composed of the η phase, coarse ζ phase, and fine ζ phase. Their corrosion potential is Eη-Zn=-1.140±0.003 V, Efine-ζ=-1.052±0.003 V, and Ecoarse-ζ=-1.036±0.002 V. The presence of fine ζ phases can form a thick passivation film on the surface of the coating. The thickness of the passivation film for the outburst and flat ζ phase layers is 5.31 nm and 6.47 nm, respectively. The more uniform the distribution of fine ζ phases, the thicker the passivation film. The corrosion types of the outburst phase layer are mainly local corrosion and pitting corrosion, and the flat phase layer is mainly uniform corrosion. The corrosion products of η phase are ε-Zn(OH)2, 4Zn(OH)2.ZnCl2, Zn5(CO3)2(OH)6, and Zn5(Cl2)(OH)8.H2O. The corrosion products of ζ phase are Fe2O3, ZnO, and Zn(OH)2.

A smartphone-based electrochemical sensing platform for the portable and simultaneous determination of flavonoids in Citri Reticulatae Pericarpium

BackgroundThe efficient and timely determination of polymethoxylated flavones (PMFs, primarily nobiletin and tangeretin) and flavanone glycosides (primarily hesperidin) in Citri Reticulatae Pericarpium (CRP) is of paramount importance for the production of CRP and the evaluation of its efficacy. Conventional analytical methods including chromatography-based approaches commonly provide high sensitivity and selectivity, but require bulky equipment and complicated procedures performed by professional technicians and are thus inconvenient in practical applications. Therefore, there is a clear need for portable and miniaturized sensing platforms that can rapidly and simultaneously detect PMFs and hesperidin in CRP product. ResultsA state-of-the-art three-dimensional porous graphene electrode was first fabricated by direct laser scribing of a poly(ether-ether-ketone) (PEEK) film for electrocatalysis of nobiletin, tangeretin and hesperidin. Kinetic analysis was conducted to investigate the reaction mechanisms of these three flavonoids at such prepared PEEK-laser induced graphene (PEEK-LIG) electrodes. Since the as-prepared PEEK-LIG electrodes exhibited high electrocatalytic efficiency towards these three flavonoids, a portable electrochemical sensing platform assembled with a smartphone, a miniatured electrochemical workstation, and an integrated PEEK-LIG microchip was developed. Consequently, the developed portable electrochemical sensing platforms exhibited great sensitivity and low detection limits for both PMFs and hesperidin. More importantly, tests conducted on real CRP extract samples demonstrated that the developed portable electrochemical sensing platform exhibited high validity, high reliability, as well as excellent reproducibility. SignificanceThis is the inaugural report on the portable and simultaneous determination of PMFs and hesperidin in the pericarp of Citrus Reticulata, which may be utilized for differentiating CRP products. Furthermore, the portable and powerful electrochemical sensing platforms developed could also potentially be applied for a wide range of analytes, thanks to their simple and rapid fabrication and determination processes.

Corrosion Behavior of Al-Containing CoNiV Medium Entropy Alloy Coating Fabricated by Laser Cladding.

CoNiV medium entropy alloys (MEAs) have been widely recognized for their superior corrosion resistance. Nonetheless, their extensive application has been hindered by high production costs and complex fabrication processes. In this study, CoNiVAlx MEA coatings were synthesized on AISI 304 stainless steel substrates via laser cladding technology. The microstructure, phase composition, corrosion resistance, and corrosion mechanisms of the coatings were systematically investigated by using advanced characterization techniques, including optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, and electrochemical workstation analysis. The ratio of O2-/OH- in the passivation film of the coated surface exhibited a gradual increase with the addition of Al. The formation of the Al-containing precipitated phase L21 was observed at x = 0.3 and 0.4. The results demonstrated that moderate Al doping (x ≤ 0.2) enhanced corrosion resistance by improving the stability of the passivation film and reducing the thermodynamic tendency toward corrosion. In contrast, excessive Al doping (x > 0.2) led to the formation of the L21 phase, which increased the susceptibility to localized corrosion, thus compromising the overall corrosion resistance.

Workshop on “Cutting-Edge Scientific Instruments and Training on XRD, ICP-MS, BET and Multichannel Electrochemical Workstation” at University of Ladakh, UT of Ladakh

Workshop on “Cutting-Edge Scientific Instruments and Training on XRD, ICP-MS, BET and Multichannel Electrochemical Workstation” at University of Ladakh, UT of Ladakh

In Situ Observation and Electrical Signal Analysis of Different Bubble Detachment Modes on Microelectrode Surface

The deactivation of the reaction surface caused by bubble covering is an important factor that causes the decrease in the efficiency of water electrolysis. By combining an electrochemical workstation with a high-speed camera, the evolutionary properties of hydrogen bubble and potential were obtained on a horizontal microelectrode with a diameter of 100 μm. During the electrolysis, individual bubbles evolved periodically on the electrode surface. Under the influence of electrode adsorption, the detachment diameter of the bubble is independent of current density, but with the increase of current density, the bubble detachment frequency increases. With the increase of ethylene glycol (EG) concentration, the bubble detachment frequency increased. When the concentration of EG is greater than 7.5 g l−1, the surface tension of the solution is lower than that of water, at which time the detachment mode of the bubble changes. Separating the resistance caused by the bubbles from the total resistance, it was found that the additional resistance caused by the bubbles rapidly became smaller as the EG concentration increased until the EG concentration reached 7.5 g l−1. The total resistance decreases first and then increases when the EG concentration is greater than 3 g l−1.

Fe-based amorphous reinforced CoCrFeNi HEA composite coating prepared by laser cladding

316L stainless steel (316L SS) is easy to be damaged due to poor corrosion and wear resistance, the preparation of composite coating with excellent corrosion and wear resistance properties on the surface can lengthen its service life. In this aspect, Fe-based amorphous CoCrFeNi high entropy alloy (HEA) composite coating was prepared on 316L SS by laser cladding. The microstructure, phase, microhardness, wear and corrosion resistance of the coatings were analyzed by scanning electron microscope (SEM) equipped with energy disperse spectroscopy (EDS), X-ray diffraction (XRD), Vickers hardness tester, electrochemical workstation, and the friction and wear tester. The results show that the phase composition of the coatings was FCC solid solution. The microstructure of the coatings gradually evolved from regular cellular crystals to irregular amorphous structures, while the microhardenss of each coating changed little. The wear and corrosion resistance of the coatings was better than that of the substrate. When the content of Fe-based amorphous is 8%, the properties of the coating are the best.

A new strategy to prepare ammonium aluminum carbonate hydroxide using plasma electrolytic oxidation in electrolyte containing carbon nanotubes

In this work, a plasma electrolytic oxidation (PEO) technique was used to prepare ammonium aluminum carbonate hydroxide (AACH) in an electrolyte containing carbon nanotubes (CNTs). CNTs were also involved in the composite coating on the surface of 6063 aluminum alloy. The formation mechanism of AACH and effects of CNTs on the microstructure and corrosion behavior of the PEO coatings were investigated. The surface morphology, pore distribution, phase composition, functional groups and electrochemical characteristics of the PEO composite coatings were examined using scanning electron microscopy (SEM), Image Pro software, X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR) and electrochemical workstations, respectively. Results showed that the rod-like AACH was generated around the discharge channel by reacting between ammonia, carbon dioxide and AlOOH under transient high temperature and high pressure environment with the presence of CNTs. The surface micropores of the composite coatings were enlarged due to the excellent electrical conductivity of CNTs. With the by addition of CNTs of 1.5 g/L, the self-corrosion current of the coating was the smallest, and the polarization resistance Rp was larger than that of 1.0 g/L and 2.0 g/L CNTs.

Corrosion resistance of zinc-magnesium-aluminium alloy coated steel in marine atmospheric environments

In this study, a salt-spray accelerated experiment was conducted as a simulated corrosion test of hot-dip galvanised zinc-magnesium-aluminium-coated alloy steel under a simulated marine atmospheric environment. In addition, scanning electron microscopy, confocal microscopy, X-ray diffraction, and electrochemical workstations were used to conduct analyses on the macro-morphology, microstructure, corrosion product composition, etc. after the corrosion test. Furthermore, the role of Mg in the corrosion resistance of zinc-magnesium-aluminium alloy steel sheets was determined. The research results indicated that in a marine atmospheric environment, zinc-aluminium-magnesium alloy steel has excellent corrosion resistance, and its external coating provides protection to the substrate. In a marine atmospheric environment, the corrosion products of zinc-magnesium-aluminium alloy steel mainly include Al2O3, AlOOH, zinc hydroxychloride (Zn5(OH)8Cl2·H2O), layered bimetallic hydroxides (Mg6Al2(OH)16CO3·4H2O), ZnO, and MgCO3·H2O. The addition of magnesium to galvanised sheets facilitates the formation of insoluble corrosion products, which protect the iron substrate.

Electrochemical Lateral Flow Immunoassay with Built-In Electrodes for Ultrasensitive and Wireless Detection of Inflammatory Biomarkers.

Paper-based lateral flow immunoassays (LFIAs) are cost-effective, portable, and simple methods for detection of diverse analytes, which however only provide qualitative or semiquantitative results and lack sufficient sensitivity. A combination of LFIA and electrochemical detection, namely, electrochemical lateral flow immunoassay (eLFIA), enables quantitative detection of analytes with high sensitivity, but the integration of external electrodes makes the system relatively expensive and unstable. Herein, the working, counter, and reference electrodes were prepared directly on the nitrocellulose membrane using screen printing, which remarkably simplified the structure of eLFIA and decreased the cost. Moreover, a horseradish peroxidase (HRP)-based electrochemical signal amplification strategy was used for further increasing the analytical sensitivity. HRP captured on the working electrode can catalyze the oxidation of tetramethylbenzidine (TMB) to form the TMB-TMBox precipitate on the electrode surface, which as an electrochemically active product can output an amplified current for quantification. We demonstrated that the eLFIA could detect low-abundant inflammatory biomarkers in human plasma samples with limits of detection of 0.17 and 0.54 pg mL-1 for interleukin-6 and C-reactive protein, respectively. Finally, a fully portable system was fabricated by integrating eLFIA with a flexible and wireless electrochemical workstation, realizing the point-of-care detection of interleukin-6.

Enhanced visible-light photocatalytic degradation of oxytetracycline hydrochloride by Z-scheme CuO/Bi2WO6 heterojunction

Oxytetracycline hydrochloride (OTC) has a complex structure that makes it difficult to biodegrade. Photocatalysis is an effective method for addressing OTC pollution. In the present study, a CuO/Bi2WO6 Z-scheme heterojunction was constructed for the photocatalytic degradation of OTC via the hydrothermal method. XRD, SEM, TEM, XPS, UV–vis DRS, PL, FT-IR, BET, and Electrochemical workstation were used to analyze the morphological features, crystal structure, light absorption properties, and photoelectrochemical properties of the catalyst. These results revealed that the enhanced photocatalytic ability was due to the increased absorption of visible light and the improved migration and separation of electron-hole pairs facilitated by the fabricated heterojunction. The optimized CuO/Bi2WO6 heterojunction demonstrated a superior OTC removal efficiency of 86.3 % under visible light irradiation, approximately 2.6 times higher than pure Bi2WO6. Furthermore, the removal efficiency of OTC remained around 80 % even after five cycles. Free radical trapping experiments and ESR characterization indicated that •O2- and h+ were the main active substances. Finally, the Z-scheme electron transfer mechanism for the degradation of OTC by the CuO/Bi2WO6 heterojunction was proposed. And the intermediates were determined by LC-MS to speculate on possible OTC degradation pathways during the photocatalytic process. Thus, this study provides valuable insights into designing highly efficient Z-scheme heterojunctions to remove organic pollutants using a simple hydrothermal method.

Iron nanowire/carbon microsphere composite flexible fabric strain sensor for human motion monitoring

People pay more and more attention to sports and health, especially the goal of sports recovery and scientific sports is more and more clear. In order to avoid human injury caused by unreasonable sports, it is necessary to carry out real-time detection of human motion state. In this paper, the motion state of human body was taken as the test object, a flexible strain sensitive material combining iron nanowires and carbon microspheres was proposed, and polyester fabric was introduced as the sensor substrate to construct a sandwich structure flexible fabric strain sensor. Then a mechanical test platform was built to carry out mechanical property testing and practical application verification research. The mechanical test results show that the iron nanowires/carbon microspheres flexible fabric strain sensor has good linearity, the response time is 42 ms, and the hysteresis error is approximately 8.7 %. Finally, the flexible fabric strain sensor is fixed on the part of the human body that needs to be detected, and the electrical signal curve of the response is output by the electrochemical workstation. Through the analysis of the response curve, it can be seen that the iron nanowires/carbon microspheres flexible fabric strain sensor prepared in this paper has great potential in human movement health monitoring.

Microstructure, corrosive-wear and electrochemical performance of laser cladded NiTi–xAl2O3 coatings in 3.5%NaCl solution

PurposeThe aim of this study is to investigate the effects of Al2O3 mass fraction on the corrosive-wear and electrochemical performance of NiTi coating in 3.5% NaCl solution.Design/methodology/approachThe NiTi–xAl2O3 coatings were fabricated on S355 steel by laser cladding, and their corrosive-wear and electrochemical performance were investigated using a wear tester and electrochemical workstation, respectively.FindingsThe wear rates of NiTi–5%Al2O3, –10%Al2O3 and –15%Al2O3 coatings are 82.33, 54.23 and 30.10 µm3 mm−1 N−1, respectively, showing that the wear resistance of NiTi–15%Al2O3 coating is the best. The wear mechanism is abrasive wear, which is attributed to the increase of coating hardness by the Al2O3 addition. The polarization resistance of NiTi–5%Al2O3, –10%Al2O3 and –15%Al2O3 coatings is 3,639, 5,125 and 10,024 O cm2, respectively, exhibiting that the NiTi–15% Al2O3 coating has the best corrosion resistance.Originality/valueThe roles of Al2O3 in the corrosive-wear and electrochemical performance of NiTi–xAl2O3 coating were revealed through the experimental investigation.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2024-0044/

Measurement of Zinc Ions in Seawater Samples Using a Microfluidic System Based on the GR/CeO2/Nafion Material.

Considering that heavy-metal contamination of seawater is getting worse, building a quick, accurate and portable device for detecting trace zinc in seawater in real time would be very beneficial. In this work, a microfluidic system was developed that includes a planar disc electrode, a micro-cavity for detection, an electrochemical workstation, a computer, a container for waste liquid reprocessing, an external pipeline and other components as well as a graphene/cerium oxide/nano-cerium oxide/Nafion composite membrane was used to modify the planar disc electrode (GR/CeO2/Nafion/Au) to investigate the electrochemical behaviour of Zn(II) using cyclic voltammetry, square-wave voltammetry and orthogonal test methods. Under optimal experimental conditions, the peak reaction current of Zn(II) showed a good linear relationship with the concentration of Zn(II) in the range of 1-900 μg/L with a correlation coefficient of 0.998, and the detection limit of the method was 0.87 μg/L. In addition, the microfluidic system had good stability, reproducibility and anti-interference. The system was used for determining zinc ions in real seawater samples, and the results were very similar to those of inductively coupled plasma-emission spectrometry, demonstrating the practicality of the system for the detection of trace zinc.

Effect of Substrate Preheating Temperature on the Microstructure and Properties of Laser Cladding Fe/TiC Composite Coating

In this study, Fe/TiC composite coating was fabricated on the surface of 65Mn steel using substrate preheating combined with laser cladding technology. In order to characterize the impact of various preheating temperatures, four coatings were fabricated on a 65Mn substrate using laser cladding at different temperatures (ambient temperature, 100 °C, 200 °C, and 300 °C). The microstructures and properties of four Fe/TiC composite coatings were investigated using SEM, XRD, EDS, a Vickers microhardness meter, a wear tester, and an electrochemical workstation. The research results show that the cladding angle of the Fe/TiC composite coating initially increases and then decreases as the substrate preheating temperature rises. The solidification characteristics of the Fe/TiC composite coating structure are not obviously changed at substrate preheating temperatures ranging from room temperature to 300 °C. However, the elemental distribution within the cladding layer was significantly influenced by the preheating temperature. An increase in the preheating temperature led to a more uniform elemental distribution. Regarding the comprehensive properties, including hardness, wear characteristics, and corrosion resistance, the optimum substrate preheating temperature for the cladding layer was found to be 300 °C.

The Corrosion Resistance of Tartaric-Sulfuric Acid Anodic Films on the 2024 Al Alloy Sealed Using Different Methods

Tartaric-sulfuric acid anodic (TSA) films were prepared on the surface of the 2024 Al alloy. These films were sealed with cerium salts at 25 °C and 65 °C, hot water, and dichromate. The morphology and corrosion resistance of the anodic films were investigated using a field emission scanning electron microscope/energy-dispersive spectrometer, an electrochemical workstation, an acidic spot test, and an immersion test. The results indicated that the surface of the TSA film sealed with cerium salt at 65 °C had a slightly lower cerium content compared to the TSA film sealed at 25 °C. It was found that increasing the sealing temperature of cerium salt could enhance the corrosion resistance of the TSA film. After immersion in a 3.5 wt.% NaCl solution for 336 h, no obvious corrosion pits were observed on the surface of the TSA film sealed at 65 °C, whereas many larger corrosion pits appeared on the surface of the TSA film sealed at 25 °C. The improved corrosion resistance of the TSA film sealed at 65 °C could be attributed to the synergistic effect of cerium oxide deposition and the hydration reaction. The corrosion resistance of the TSA film sealed at 65 °C was significantly better than that of the film sealed with hot water, but it was still lower than that of the TSA film sealed with dichromate.

Effect of solution temperature on the microstructure and properties of ceramic coating on the surface of 2024 aluminum alloy

This study investigates the influence of the 2024 aluminum alloy was treated with solution before ceramic treatment on the microstructure and characteristics of ceramic coatings applied to 2024 aluminum alloy substrates. The microhardness, corrosion resistance, and microstructural properties of these ceramic coatings were assessed using a microhardness tester, an electrochemical workstation, and a scanning electron microscope. The findings indicate that pre-treatment involving solution treatment significantly enhances the hardness and corrosion resistance of 2024 aluminum alloy ceramic coatings. Notably, when the solution temperature was maintained at 460 °C, the most rapid decrease in current density was observed during the ceramization process, resulting in the attainment of the lowest final stable current density. This particular condition yielded ceramic coatings with optimal hardness and corrosion resistance, with hardness exhibiting a remarkable increase of 48.9 HV, self-corrosion potential rising by 0.207 V, and polarization resistance surging by 5310.7 Ω. Moreover, the surface of the ceramic coating displayed remarkable smoothness and was devoid of discernible defects such as cracks or looseness. In light of these findings, it can be concluded that the optimum solution temperature for achieving these desirable properties is 460 °C. This conclusion is derived from a comprehensive analysis encompassing both the morphology and corrosion resistance of ceramic coatings.

Preparation of Silicone Coating and Its Anti-Ice and Anti-Corrosion Properties

To enhance protection against corrosion and ice on iron metal material in frigid zones, an organic silicone resin coating was prepared using four monomers. Its structure and performance was analyzed via infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and thermal analysis (TG). Corrosion resistance of coating was tested by saltwater resistance and salt spray resistance and assessed using an electrochemical workstation, alongside anti-icing tests. The results showed that the organic silicone resin was successfully synthesized. The coatings could delay freezing onset by one-third compared to controls in low temperatures, with a detachment time also reduced by one-third, indicating excellent corrosion and ice resistance. The methylphenyl silicone resin had good anti-corrosion and anti-ice properties, with a low corrosion current density (icorr) of 0.8793 μA/cm2 and a high charge transfer resistance (Rct) of 24,930 Ω·cm2 in saline.

Influence of Additives on the Macroscopic Color and Corrosion Resistance of 6061 Aluminum Alloy Micro-Arc Oxidation Coatings.

In this study, we successfully employed the plasma electrolytic oxidation (PEO) technique to create a uniform white ceramic layer on the surface of the 6061 aluminum alloy using K2ZrF6 and Na2WO4 as colorants. A scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS) and X-ray diffraction (XRD) were used to characterize the coatings, and we used an electrochemical workstation to test their corrosion protection properties. The corrosion resistance of the coatings was analyzed using potentiodynamic polarization curves. The results showed that K2ZrF6 addition whitened the coating with ZrO2 as the main phase composition, inhibiting Al substrate depletion and enhancing coating corrosion resistance. A small amount of Na2WO4 decreased the coating's L* value, successfully constructing ceramic coatings with L* (coating brightness) values ranging from 70 to 86, offering broad application prospects for decorative coatings.

Highly selective oxidation of biomass-derived alcohols and aromatic alcohols to aldehydes over Ti3C2-TiO2 nanocomposites under visible light

Ti3C2Tx is a two-dimensional (2D) material belonging to the MXenes family. It has a unique combination of functional features that make it appropriate for a wide range of fascinating applications, including supercapacitors, batteries, strain sensors, photocatalysis, and more. In this study, we report a synthesis of Ti3C2-TiO2 nanocomposites with tight interfacial contact that has been successfully fabricated by in situ development of TiO2 nanoparticles (NPs) on the surface of Ti3C2Tx nanosheets (NSs) via a simple and cost-effective hydrothermal process. The catalysts are well characterized by various sophisticated techniques, including X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), Brunauer-Emmett-Teller (BET), CHI660E electrochemical workstation, and HRTEM. The photocatalytic performance of pure Ti3C2Tx, Ti3C2-TiO2 (MT1), and Ti3C2-TiO2 (MT5) nanocomposites was evaluated by highly selective photo-oxidation of biomass-derived furfuryl alcohol (FA), cinnamyl alcohol, vanillin alcohol, and various aromatic alcohols to the corresponding aldehyde with >99% selectivity for all the alcohol substrates under visible light (385–740 nm). Photocatalytic oxidation results revealed that Ti3C2-TiO2 (MT5) has superior photocatalytic activity than Ti3C2-TiO2 (MT1) and pure Ti3C2Tx NSs. The exceptional photocatalytic activity was attributed to the composite's unique morphology and characteristics.

Laser cladded Co08–xTi3AlC2 coatings: Microstructure, corrosive–wear and electrochemical corrosion

MAX phase played the positive role during the corrosive–wear process of metal coatings, and Ti3AlC2 was added into Co08 coating by laser cladding to improve its corrosive–wear and electrochemical properties. The effects of Ti3AlC2 mass fraction on the corrosive–wear and electrochemical properties of obtained coatings in 3.5 % NaCl solution were investigated using a reciprocating wear tester and electrochemical workstation, respectively. The results show that the Co08–xTi3AlC2 coatings are composed of Co (Ni, Cr, W, Mo), AlFe and Ti3AlC2 phases, and their hardness is increased with the Ti3AlC2 mass fraction. The average coefficients of friction of Co08–5 %Ti3AlC2, –10 %Ti3AlC2 and –15 %Ti3AlC2 coatings are 0.56, 0.47, and 0.41, respectively, and the corresponding wear rates are 418.99, 389.67, and 339.33 μm3 N−1 s−1, respectively, showing that the Co08–15 %Ti3AlC2 coating has the best friction reduction and wear resistance among the three kinds of coatings. The wear mechanism of Co08–5 %Ti3AlC2, –10 %Ti3AlC2 and –15 %Ti3AlC2 coatings are abrasive wear, adhesive wear, and abrasive wear/adhesive wear, respectively. Moreover, the corrosion resistance of Co08–xTi3AlC2 coatings is increased by the Ti3AlC2 mass fraction, which is attributed to the protection role of corrosion products by the addition of Ti3AlC2.