bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Mg2+ on the Corrosion Behavior of Zinc
Authors: Tada Eiji , Tsurumaki Yumiko , Nishikata Atsushi 
Published: February 2020

Zinc-coated steels have been widely used in various industrial fields such as automobiles and construction since they have excellent corrosion protection in atmospheric corrosion environments. To improve corrosion resistance of the coating, zinc-alloy coatings containing Mg have been develped and they have demonstrated superior corrosion resistance in terms of duration to appearance of red rusts on steel compared with zinc coatings. However, the effect of Mg on the improvement of corrosion resistance of the zinc-alloy coatings is still unclear. In this study, the effect of Mg2+on the corrosion behavior of zinc in Cl-containing aqueous environmnts is investigated by electrochemical measurments and surface analysis.
A pure zinc plate (purity: 99.5%) was used as a sample. The zinc plate was grounded with SiC papers up down to JIS #2000 grit and then rinsed in EtOH for several minutes. Test solutions used in this study were aqueous solutions of 1 M MgCl2and 2 M NaCl. Corrosion potential and polarization resistance for zinc were monitored during the immersion in the test solutions. The reciprocal of polarization resistance was used as a measure to evaluate corrosion rate. After the immersion, the surface of zinc was investigated by SEM-EDX, XRD and FE-AES.
From the results of the reciprocal of polarization resistances measured in the test solutions, it was confirmed that corrosion rate of zinc in MgCl2 is lower than that in NaCl during the immersion. Furthermore, it was also found that the corrosion rate in MgCl2 decreases obviously ca. 4 h after immersion in the solution. At this time, corrosion potential for zinc in MgCl2 shifted in the noble direction. These results indicate that corrosion rate of zinc is decreased due to the inhibition of anodic dissolution of zinc. From the results of surface observation and anaysis of zinc after the immersion, it was found that finer corrosion products of zinc were formed in the case of MgCl2 compared with that of NaCl. This result suggests that the differenrce in the morphology of zinc corrosion products can be related to the difference in the corrosion resistances in both solutions.
Effect of Sulfate Ions on Repassivation Behavior of Crevice Corrosion on Type 316L Stainless Steel
Authors: Aoyama Takahito , Sugawara Yu , Muto Izumi , Hara Nobuyoshi 
Published: February 2020

Crevice corrosion is known to be a serious problem of stainless steel structures in Cl- containing environments. The growth and repassivation behavior of crevice corrosion are significantly influenced by the solution composition of corrosion environments. To clarify the repassivation behavior of crevice corrosion, an in situ observation is a promising technique. This is because the quantitative relationship between current values and corrosion morphology could be analyzed. The current distribution inside the crevice can be estimated from the spreading of crevice corrosion depth. In this study, an in situ observation technique was applied to the study of the crevice corrosion of stainless steel. In addition, to clarify the effect of the solution composition outside the crevice on repassivation behavior, an electrochemical flow cell was newly designed.
Type 316L stainless steel was used as specimens. The specimens were heat-treated at 1373 K for 3.6 ks and then water-quenched. An electrochemical flow cell was fabricated (Fig. 1). The crevice was made by pressing a glass sheet to the specimen surface, and the specimen was polarized at 0.25 V (vs. Ag/AgCl, 3.33 M KCl). Crevice corrosion tests were initially performed in a flowing 1 M NaCl solution (298 K). During the corrosion tests, the corrosion behavior of the specimen surface inside the crevice was observed using an optical microscope through the glass sheet, and then the time-lapse video was produced by capturing one frame per 10 seconds. In some cases, the flowing solution was changed from 1.0 M NaCl to 0.88 M Na2SO4, after the initiation of the crevice corrosion. The solution was changed when the current reached a value of 100 µA.
Figure 2a shows the time variations of the current during the crevice corrosion tests. In the case of test A, the solution was not changed. In test B, the solution was changed from NaCl to Na2SO4 when the current reached the value of 100 µA. In both cases, the current first decreased to ca. 5 µA with the lapse of time and at about 400 s, it became to increase rapidly due to the initiation of crevice corrosion. In test A, the current increased up to ca. 5 mA. On the other hand, in test B where the solution was changed, the current decreased after reaching a maximum value of 3 mA at ca. 2.5 ks. The results of in situ observation of the specimen surface are shown in Fig. 2b. In test A, the corroded area propagated along the crevice mouth (Fig. 2b). At the beginning of crevice corrosion in test B, its propergation was similar to that of test A. When the current began to decrease at ca. 2.5 ks, the direction of corrosion propagation changed toward the inside of crevice (Fig. 2c). Finally, when the current decreased to ca. 1.2 µA, no lateral propagation of the corroded area was observed, suggesting that the repassivation inside the crevice was completed.

Figure 1
Extending the Life-Time of Low Cost Fuel Cells
Authors: Bedouet Max 
Published: February 2020

Extending the bipolar plate lifetime of low-cost fuel cell.
Energy conversion sources that offer lower carbon emissions, increased efficiency and reduced environmental impact at a competitive cost are a key requirement for future low carbon transport and stationary power generation applications.Fuel cells are promising candidates but widespread uptake has so far been hindered by the high cost of materials and manufacturing in addition to limited durability under realistic operating conditions. There is a clear need for a lower cost approach but without sacrificing performance or durability.
Bipolar plates are responsible for collecting current, supplying the fuel to the MEA as well as exhausting water produced at the cathode side1. Metallic bipolar plates must be resilient, non-porous, conductive with a low contact resistance and obviously cheap for mass market penetration2. The US Department of Energy (DoE) has introduced target cost plans for 2020 on different PEM fuel cell components, including bipolar plates3. The technical plan states that the corrosion rate must be below 1 µA.cm-2 and that an interfacial contact resistance must be below 10 mΩ.cm2 at a compaction pressure of 140 N.cm-2. These condition has to be attained with a cost below 3 $kW-1. Bipolar plates account for 45-60 % of the stack cost, 80 % of the weight, and almost all the volume of the PEM fuel cell stack.
The flexiplanar approach uses a metallic substrate mounted on a printed circuit board (PCB) in order to produce a low cost cell. Copper is a strong candidate for this purpose: it is robust, has a high conductivity and a low contact resistance as well as a possibility of scalable hydroforming or stamping4, which is an important feature in order to produce a flow field plate. However, due to the harsh conditions within the fuel cell stack such as a high potential and temperature, the copper interface must be protected by a coating. Coatings applied on the flow field plate must have a good electrical conductivity, a low contact resistance and also have to be resilient to fuel cell operating conditions i.e. 120 °C and 1.2 V. In recent years, there has been an increasing amount of literature on carbon polymer blend used as metallic substrate protector19
,
20
,
21. Carbon-polymer mixtures are commercially available at reasonably affordable prices. Nevertheless, they are also likely to be corroded due to carbon micro-particles dispersed in the polymer. Hence further investigation needs to be done in this poorly understood area.
1 Polymer Fuel Cells - Cost reduction and market potential, C. Trust, 2012.
2 C. Spiegel, Designing and Building Fuel Cells, 2007.
3 T. Plan and F. Cells, 2015, 1–49.
4 ASM International, Copper and Copper Alloys, ASM International, 2001.
5 W. L. Wang, S. M. He and C. H. Lan, Electrochim. Acta, 2012, 62, 30–35.
6 Y. Show and K. Takahashi, J. Power Sources, 2009, 190, 322–325.
7 Y. B. Lee and D. S. Lim, Curr. Appl. Phys., 2010, 10, S18–S21.
Novel Silane-Polymer Composite Coating for Corrosion Protection of Mg-Zn-Al Alloy Against Corrosion in NaCl Solution
Authors: BinSabt Mohammad , Al-Kharafi Faizah M , Abditon Maryam , Galal Ahmed 
Published: February 2020

The electrochemical behavior of magnesium-aluminum-zinc alloy with composition Mg(93)-Zn(1)-Al(6) alloy is studied in 3.5% NaCl containing aqueous electrolytes. Potentiodynamic polarization and electrochemical impedance (EIS) measurements show a noticeable decrease in polarization resistance indicating the spontaneous dissolution of the alloy. The alloy was treated with a novel silane-polymer coating that proved effective in protecting the surface against corrosion. The protecting film is composed of 1,2-bis(triethoxysilyl)ethane-poly(vinyl alcohol) hybrid (TESE-PVA). The hybrid film was administered to the alloy surface using different approaches; sequential mechanical dropping and spin-coating of TESE-PVA or PVA-TESE, a mixture of TESE-PVA, and PVA was cross-linked and sequentially administered with TESE.
The alloy surface was examined before and after exposure to the NaCl solution using field emission electron microscopy/energy dispersive analysis with x-ray and x-ray photoelectron spectroscopy. Severe surface damage is noticed for the bare alloy with the formation of oxides, hydroxides and oxy-salts mainly of magnesium. The film is optimized using different concentration ratios between PVA-TESE, sequence of application and film thickness. The Mg-alloy coated with the “optimized” hybrid coating was tested for extended time exposure in the chloride solution and the coating proved effective in protecting the Mg-alloy. The film thickness and surface wettability were also determined with the film displaying relative increase in the hydrophobic character. Surface enhanced Raman spectroscopy (SERS) was used to characterized the structure of the film coating over the surface before and after exposure to the corroding medium.
Behaviour of Nanostructured Si-Based Anode Materials Studied By Atom Probe Tomography and Hard X-Ray Photoelectron Spectrocopy
Authors: Renner Frank Uwe , Pradeep Konda Gokuldoss , Zheng Yueming 
Published: February 2020

Lithium-ion batteries (LIB) are considered for electric vehicles (EV) as well as for home or off-grid energy storage for example in combination with photovoltaics. These specific applications drive the research on high energy density, cost-effective, safe and environmental friendly battery materials. To obtain deeper insight into the reaction mechanisms advanced characterization such as in-situ TEM or in-situ XRD1 are often used in combination with simplified model systems. For LIB anodes Si has the highest specific capacity among all anode materials. However, the mechanical fatigue (lack of microstructural integrity) associated with large volume expansion of pure Si during the lithiation process has hindered their wider use for commercial applications so far. Also, there are a series of side reactions which happen at the surface forming the solid electrolyte interface (SEI). In this work we investigate the role of mechanically confined nanocrystalline Si particles being embedded in a SiTiNi matrix2. Samples are produced by melt-spinning from a rapidly solidified SiTiNi alloy. The ribbon exhibits a nanocomposite microstructure with nano-Si particles (~50-200 nm) as potential sites for Li-storage embedded in an amorphous matrix of SiTiNi (STN). Such alloys have shown potential for anode materials in high capacity Li-ion batteries. Systematic lithiation and de-lithiation cycles were performed and selected samples after different cycles were investigated using Atom Probe Tomography (APT) to understand the Li diffusion mechanism in and out of the Si particles. We consider Atom Probe Tomography as a powerful tool to understand the phase changes at an atomic level3. Aided by Focus Ion Beam (FIB), we can address the nm-scale element distribution in any local structure. On the other hand, Hard X-Ray Photoelectron Spectroscopy (HAXPES) is adopted for a detailed SEI study. The employed high energy X-ray beams can probe deeper information of core level photoemission
[1] Bach, P.; Valencia-Jaime, I.; Ruett, U.; Gutowski, O.; Romero, A.H.; Renner, F.U. Chemistry of Materials (2016), doi: 10.1021/acs.chemmater.5b04719;
Renner, F.U.; Kageyama, H.; Siroma, Z.; Shikano, M.; Schröder, S.; Gründer, Y.; Sakata, O. Gold Model Anodes for Li-Ion Batteries: Single Crystalline Systems Studied by In Situ X-ray Diffraction, Electrochim. Acta 2008, 53, 6064-6069.
[2] Son et al. “A Highly Reversible Nano Si Anode Enabled by Mechanical Confinement in an Electrochemically Activated LiXTi4Ni4Si7 Matrix.” Advanced Energy Materials 2 (2012), 1226.
[3] Diercks et al., Microscopy of Chemical and Mechanical Heterogeneities in Lithium Cobalt Oxide, Microscopy and Microanalysis 21 (2015), 523.
(Invited) Electrochemical Impedance Study on Anodic Dissolution of Magnesium in Sodium Sulfate Solution
Authors: Umetsu Keita , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki 
Published: February 2020

Magnesium and its alloys are widely used in the industrial field such as the auto-mobile and electronic devices. However, the high reactivity of Mg and its alloys in the aqueous solution limits the application of magnesium. The hydrogen evolution rate on dissolving magnesium is increased when the applied anodic potential is increased, which is called the Negative Difference effect (NDE)1). Some mechanisms related to the anodic dissolution and hydrogen evolution of magnesium have been proposed in previous researches 1-3). Williams et al.2) investigated the local current on the anodically polarized magnesium surface by in-situScanning Vibrating Electrode Technique (SVET). They found that the anodic dissolution of magnesium is shown to be highly localized in nature and accompanied by significant cathodic activity. The reactions for the anodic dissolution of magnesium and hydrogen evolution occurred on the magnesium surface are expressed by the following reactions.
Mg → Mg2+ + 2e
-(1)
2H2O + 2e
- → H2 + 2OH-(2)
They2) implied that the hydrogen evolution on the magnesium surface is accelerated by the applied anodic potential. Cain et al.3)supported this theory by investigation using inductively coupled plasma optical emission spectroscopy (ICP-OES) and Rutherford backscattering spectrometry (RBS). However, the anodic dissolution mechanisms of magnesium are not well understood yet.
Our group have been investigating magnesium dissolution by 3D impedance spectroscopy. In our previous research, it was found that the inductive loops appeared in impedance spectra of magnesium are originated from Volmer and Heyrovsky reaction by calculating Faraday impedance 4). In the present study, we focus on the localized reaction of magnesium dissolution and hydrogen evolution. The local electrochemical impedance spectroscopy (LEIS)5)combined with 3D impedance spectroscopy was applied to the investigation of anodic dissolution of Mg.
Reference:
[1] G. Song, A. Atrens, D. Stjohn, J. Nairn, Y. Li, Corrosion Science, 39, 855-875 (1997).
[2] G. Williams, N. Birbilis, H.N. McMurray, Electrochemistry Communications, 36, 1-5 (2013).
[3] T. Cain, S. B. Madden, N. Birbilis, J. R. Scully, Journal of the Electrochemical Society, 162, C228-C237 (2015).
[4] K. Umetsu, Y. Hoshi, I. Shitanda, M. Itagaki 228th ECS meeting abstract, #659 (2016).
[5] V. M. Huang, S. Wu, M. E. Orazem, N. Pébère, B. Tribollet, V. Vivier, Electrochimica Acta, 56, 8048-8057 (2011) .
Quantitative Reconstruction of Half-Cell Impedances of Commercial Lithium-Ion Cells By Three Electrode Measurements and Impedance Modeling
Authors: Schindler Stefan , Danzer Michael A. 
Published: February 2020

Impedance spectroscopy is a powerful tool for rating the performance and degradation of battery cells [1]. With regard to commercial cell formats, impedance acquisition and analysis is limited to the full cell impedance due to absence of an appropriate lithium reference potential to separate the shares of both half-cells. In consideration of this limitation, the equivalent electrodes are usually examined separately in symmetrical or three electrode arrangements [2, 3]. While this approach is generally suitable for qualitative estimations of the half-cell ratios, a quantitative reconstruction requires detailed knowledge of impedance contributions from the cell geometry and electrical contacts as well as an appropriate model approach to subtract the latter from the actual half-cell data.
In this study, we introduce a model-based reconstruction methodology based on a mathematical treatment of measurement data recorded on experimental full cells with suitable reference electrode. The methodology includes impedance scaling equivalent to the ratio of electrochemically active areas of experimental and commercial cell, a modulation of the geometrical contribution to the cell impedance and a correction of the purely ohmic impedance ratio to compensate the deviation of electrolyte volumes. It is shown that the subsequent application of these modification steps already yields an excellent reconstruction which can even be further refined by increasing the model discretization. The validity of the proposed methodology is cross-checked by application of distribution of relaxation times (DRT) analysis, which is a powerful mathematical tool to separate polarization contributions by their characteristic time constants [4]. Here, DRT is utilized to demonstrate the reproduction fidelity of the impedance modulation.
The presented methodology opens the door for a great bandwidth of new applications, for instance to develop iterative half-cell degradation models which can be parametrized from impedance data recorded on the (commercial) full cell at any state of degradation. Thus, it constitutes a completely refined opportunity for online applicable, non-invasive diagnosis of lithium-ion cells.

References

[1] Osaka, T.; Daikichi, M.; Hiroki, N.; J. Electrochem. Soc. 162 (2015) A2529-A2537
[2] Song, J.; Lee, H.; Wang, Y.; Wan, C.; J. Power Sources 111(2002) 255-267
[3] Chen, C.; Liu, J.; Amine, K.; J. Power Sources 96 (2001) 321-328
[4] Illig, J.; Schmidt, J.P.; Weiss, M.; Weber, A., Ivers-Tiffée, E.; J. Power Sources 239 (2013) 670-679

Figure Captions

Fig. 1: a) Exemplary nyquist plot recorded for commercial and experimental full cell (T = 25°C, SOC = 50 %). Simplified equivalent circuit structures used in the reconstruction for b) experimental full cell c) commercial cell. A reference electrode is implemented in the experimental cell to separate half-cell impedances.

Figure 1
(Invited) Evaluating Corrosion Processes in an Aluminum Alloy, AA2024, Assisted By a Consortium of Microorganisms
Authors: Paez Maritza Angelica , Alvarado Claudia , Gulppi Miguel , Gomez Grace , Sancy Mamie , Azocar Manuel Ignacio , Vejar Nelson , Blamey Jenny , Molina Paulo , Zagal Jose H 
Published: February 2020

The influence of microorganisms in the deterioration of metal surfaces is an important issue in relation to the life of metal structures, equipment, and in terrestrial, marine, and aerospace transportation. In addition, changes in processes and formulations in surface treatments, in order to respond to environmental requirements, have reduced the protective quality of anti-corrosion coatings. A good example of this is the restriction in the use of Cr (VI) in surface treatments of aluminum alloys for aeronautical applications. To this we add the fact of climate change on a global level which can make the situation moredramatic. Therefore, there is growing interest in the phenomenon of microbiologically influenced corrosion in order to design intelligent solutions and long service life.
In this we have studied the electrochemical behavior of an aluminum alloy exposed to a bacterial consortium. We have also considered the electrochemical responses of aluminum alloys exposed to some of the bacteria that make up the consortium. Thus, potentiodynamic polarization measurements and electrochemical impedance spectroscopy were performed. Moreover, the morphological changes associated to the corrosion phenomena were followed by optical microscopy and scanning electron microscopy. Furthermore, we check indirectly the enzymatic biocorrosion process, using macromolecules of a molecular catalyst adsorbed on the surface of a carbon electrode.
The identification of microorganisms was performed by sequencing of the 16S gene of ribosomal DNA (rDNA), which allowed to distinguish a number of bacteria belonging to the genera Staphylococcus, Kocuria, Nosocomiicoccus and Tersicoccus. For all microorganisms, the catalase test was positive. Electrochemical measurements and morphological characterization (SEM and AFM) of the surfaces were performed before, and after, different immersion times (1, 2, 3, 7 and 14 days) in minimum culture media, Twin (MMT), sterile and inoculated with the consortium and also, with each isolated microorganism. Impedance diagrams for all immersion times showed a capacitive behavior characterized by a single time constant. Although for short exposure times no corrosion process was evident, for longer times the resistance of aluminum oxide (Rox) decreased significantly. The enzymatic approach of corrosion was studied using pyrolytic carbon electrodes modified with cobalt phthalocyanine. These results show that the presence of microorganisms significantly alter the mechanism of oxygen reduction, particularly the reduction of oxygen to hydrogen peroxide, confirming the enzymatic approach mechanism in MIC.
Ackowledgements: The authors are grateful to CONICYT (Grant ACT1412) for financial support.
(Invited) Correlation of Electrochemical Dissolution and Impedance of Active Implant Electrodes from Platinum and Iridium
Authors: Hassel Achim Walter , Kollender Jan Philipp , Sprinzl Georg , Doll Theo 
Published: February 2020

Cardiac pacemakers and cochlear implants are examples for medical devices that make use of active electrodes from platinum, iridium or their alloys. They require relatively high voltages to stimulate body functions such as muscle contraction or nerve stimulation. From an electrochemical point of view the electrochemical window of the water based body fluids is exceeded and thus water splitting can occur. However, there is an important side reaction which has not been proven so far, that is the electrochemical dissolution of the noble metal electrodes. From a financial point of view these losses could be easily accepted in relation to other costs such as the required surgery or the hospital stay. The important point is that the minor dissolution is under suspect of being responsible for the nerve degeneration that leads to a malfunction of these devices.
In an attempt to clarify the mechanism combined experiments were performed in which electrochemical impedance spectroscopy at certain bias potentials was performed and the resulting noble metal dissolution was quantitatively monitored by an extremely sensitive analytical method the so called inductively coupled plasm mass spectroscopy (ICP-MS).
For a simulation of the in operando conditions large amplitude frequency measurements were performed to understand the relationship between dissolution rate and frequency.