bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Digital Presentation) Preparation and Characterization of PMMA-SWCNT Nanocomposites
Authors: Czapura Łukasz , Stando Grzegorz Jan , Janas Dawid 
Published: September 2023

Carbon nanotubes (CNTs) exhibit unique properties such as high tensile strength, excellent electrical conductivity, and resistance to corrosion. Unfortunately, macroscopic objects from these nanostructures do not perform equally well because the individual nanotubes do not transfer electrical charge, phonons, or stress between them sufficiently well. One possible solution to improve the properties of macroscopic ensembles from nanocarbon is to manufacture the composites with other materials like polymers, ceramics, or metals. This connection is usually beneficial. However, the properties depend strongly on the integration degree of the two compounds. For example, nanocomposites with polymers have improved mechanical (Poly(methyl methacrylate), PMMA) or electrical (in the cause of conductive polymers) properties. Many ways lead to PMMA-CNTs, but the most popular are coating (dip-coating, spin-coating, spray-coating) and dispersion methods.
One of the potential applications of these composites is as a membrane for the purification of wastewater from organic residues. Unfortunately, industrial growth in the last century has caused a reduction in the availability of pure water, so the abovementioned application of CNTs would be beneficial. However, the main problem with pristine carbon nanotube films is their structural integrity. The addition of polymer molecules could overcome this problem and lead to a new effective method of removing impurities.
The commercial single-walled carbon nanotubes (TuballTM) were used to create nanocomposites with PMMA using either dip-coating or dispersion method. Scanning Electron Microscopy (SEM), Raman spectroscopy, Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy, and mechanical testing were used to analyze composites. The nanocomposites were used to remove aromatic organic compounds dissolved in water. For model substances methyl orange, methylene blue, and fluorescein were chosen. UV-VIS spectroscopy was used to gauge the concentration of organic compounds before/after the filtration of the aqueous solution dissolved therein. The best results were for SWCNTs and PMMA-SWCNTs membranes as they removed more than 99% of chosen water impurities.
(Digital Presentation) Modification of Physicochemical Properties of Carbon Nanotubes By Chemical Functionalization
Authors: Ćwiertnia Jakub , Stando Grzegorz Jan , Janas Dawid 
Published: September 2023

Carbon nanotubes (CNTs) are still one of the most promising nanocarbon materials despite being researched for over 30 years so far. CNTs have magnificent physical and chemical properties such as appreciable tensile strength, high electrical and thermal conductivity, tunable surface character, and chemical activity. However, the amount of structural defects can strongly impact these properties. Nevertheless, from a chemical point of view, these structural damages are often necessary to integrate CNTs with different materials. One of the most popular functionalization strategies is oxidization, which increases the hydrophilicity of the material at the expense of electrical conductivity.
In our research we focused on analysis, how different reduction parameters influence changes in properties of the material. We used modified Hummers method was used to oxidize single-walled carbon nanotubes (SWCNTs) and later reduction was conducted with use of hydrogen in elevated temperature in tube furnace. The process was monitored with Raman spectroscopy, Scanning Electron Microscopy and X-ray photoelectron spectroscopy to track ongoing changes. All materials, obtained in successful synthesis, were characterized to determinate the following properties: water contact angle (WCA), electrical and thermal conductivity and Seebeck coefficient. It was observed that due to reduction Seebeck coefficient increased from 24 μV/K for oxidized material to 39 μV/K after reduction, while WCA changed from 24° to 39°. This method has potential for future modeling of their properties and improved modification process can lead to new field of applications in thermoelectric of carbon nanomaterials.
(Digital Presentation) Deconstructing Proton Transport through Atomically Thin Monolayer CVD Graphene Membranes
Authors: Kidambi Piran 
Published: September 2023

Selective proton (H+) permeation through the atomically thin lattice of graphene and other 2D materials offers new opportunities for energy conversion/storage and novel separations. Practical applications necessitate scalable synthesis via approaches such as chemical vapor deposition (CVD) that inevitably introduce sub-nanometer defects, grain boundaries and wrinkles, and understanding their influence on H+ transport and selectivity for large-area membranes is imperative but remains elusive. Using electrically driven transport of H+ and potassium ions (K+) we probe the influence of intrinsic sub-nanometer defects in monolayer CVD graphene across length-scales for the first time. At the micron scale, the areal H+ conductance of CVD graphene (∼4.5–6 mS cm−2) is comparable to that of mechanically exfoliated graphene indicating similarly high crystalline quality within a domain, albeit with K+ transport (∼1.7 mS cm−2). However, centimeter-scale Nafion|graphene|Nafion devices with several graphene domains show areal H+ conductance of ∼339 mS cm−2 and K+ conductance of ∼23.8 mS cm−2 (graphene conductance for H+ is ∼1735 mS cm−2 and for K+ it is ∼47.6 mS cm−2). Using a mathematical-transport-model and Nafion filled polycarbonate track etched supports, we systematically deconstruct the observed orders of magnitude increase in H+ conductance for centimeter-scale CVD graphene. The mitigation of defects (>1.6 nm), wrinkles and tears via interfacial polymerization results in a conductance of ∼1848 mS cm−2 for H+ and ∼75.3 mS cm−2 for K+ (H+/K+ selectivity of ∼24.5) via intrinsic sub-nanometer proton selective defects in CVD graphene. We demonstrate atomically thin membranes with significantly higher ionic selectivity than state-of-the-art proton exchange membranes while maintaining comparable H+ conductance. Our work provides a new framework to assess H+ conductance and selectivity of large-area 2D membranes and highlights the role of intrinsic sub-nanometer proton selective defects for practical applications.
References:
1. Chaturvedi et al. J. Mater. Chem. A, 2022,10, 19797-19810
Fabrication of Anion-Exchanged Electrodeposited Zn-Al Layered Double Hydroxides (LDHs) Coating on ZX21 Mg Alloy
Authors: Hsiao Wei-Lun , Chu Peng-Wei 
Published: September 2023

Because of their low density and high specific strength, Mg alloys are considered promising lightweight alloys for various applications. However, due to the high electrochemical activity and poor corrosion resistance, surface modifications of Mg alloys are needed to increase the service life. Hence, an active layered double hydroxides (LDHs) coating was investigated in this study. Owing to the brucite-like layered structure, the weakly bonded interlayer anions can be easily exchanged with other anions in the environment. With the unique anion-exchange mechanism, LDHs coating provides dual protection to the Mg alloy substrate. It can not only act as a physical barrier but also absorb aggressive anions such as Cl- and release corrosion inhibitors to the environment.
Compared to the commonly used hydrothermal method to fabricate LDHs coating, which requires high temperature and long process time, electrochemical deposition has the advantages of high deposition rates, simple experimental setup, and highly controllable process parameters. Therefore, in this study, a three-electrode electrochemical setup was used to fabricate Zn-Al LDHs coatings on a ZX21 Mg alloy. Moreover, different anions are intercalated into the interlayer galleries of the prepared Zn-Al LDHs coating through post anion-exchange processes.
Through electrochemical analysis in a 3.5 wt% NaCl solution, the prepared anion-exchanged electrodeposited Zn-Al LDHs coating improved the corrosion resistance of ZX21 Mg alloy. Electrochemical impedance spectroscopy (EIS) showed that corrosion impedance increases, while potentiodynamic polarization curves revealed that the corrosion current density (i
corr) of the coated sample was an order of magnitude lower than the ZX21 Mg alloy substrate. Besides the improvement of corrosion resistance, the formation mechanism of Zn-Al LDHs coating by electrodeposition was also investigated by electrochemical analysis and in situ optical microscopic (OM) observations. The corrosion behavior and microstructure of Zn-Al LDHs coating and the roles played by different intercalated anions will be discussed based on electrochemical analysis and microstructure characterizations.

Figure 1
Improvement of Adhesion and Corrosion Resistance of TiO2 Nanotubes on Ta6V Alloy
Authors: Eyraud Marielle , Djendel Abderrazak , Ait Ahmed Nadia , Knauth Philippe 
Published: September 2023

Titanium and its alloys are used In orthopedic and dental implants due to their good corrosion resistance thanks to the passive native film and biological compatibility. Nevertheless, the increase in life expectancy being higher that the corrosion resistance of such thin layer, several treatments were developped. Among them, electrochemical TiO2 nanotubes allow to increase the corrosion resistance, overcome the bioinert nature of a flat surface that is not favorable for cell development, but suffer of a poor adhesion on Ti surface.
The goal of this communication is to evaluate the corrosion performance as well as the adhesion properties of single and combined electrochemical treatments made on TA6V titanium alloy, including nanostructured (N), compact (C), and dual treated (NC) layers. The influence of potential used for the compact oxidation was evaluated on C and NC systems. The best potential from a corrosion point of view was determined to elaborate an optimal NC film. Given that the hydrophilicity is correlated with cellular adhesion and protein adsorption, water contact angle measurements were realized directly after the treatments and one month later. Since the surfaces became more hydrophobic by ageing, two different ways were tested to recover their initial hydrophilic behavior.
On the Passive Behavior of the Cantor Alloy in Acidic Environment
Authors: Hou Yaojun , Dou Baojie , Sun Fan , Ogle Kevin , Gharbi Oumaïma , Turmine Mireille , Vivier Vincent 
Published: September 2023

High-entropy alloys (HEA) consisting of five or more elements in equimolar or near-equimolar ratios, represent an emerging class of materials showing an exceptional combination of properties such as high strength and ductility, improved fatigue resistance, fracture toughness, and thermal stability. They show considerable potential for use as corrosion resistant alloys to support our infrastructure especially for use in extreme environments. The possibility of high corrosion resistance with single phase HEAs has been demonstrated but the absence of single primary element in the HEA makes the prediction of its corrosion resistance extremely difficult.
EIS was originally developed as a tool for corrosion research and is well suited for the identification of complex mechanism involving adsorption intermediates, and 2D and 3D formation of thin films in the nanometer range. Additionally, EIS can be used for a comprehensive description of the passive film properties. This project focus on the well-defined Cantor alloy to studies its passivation in sulfuric acid solution with various chloride ions contents. EIS and linear wseep voltammetry have been used in order to describe the passive film formation as well as the passive film stability (Fig. 1). A specific attention has been paid in order to finely describe the passive film properties as a function of the applied potential and the chloride contents.
In parallel, the resistance of the passive film was studied using the pumped-micropipette delivery/substrate collection (Pumped-MD/SC) mode of scanning electrochemical microscopy (SECM), which allows to generate a single pitting on the alloy and to study its initiation, propagation and repassivation as a function of the potential and the chloride ion concentration. This approach allows in particular to get rid of the stochastic aspect of the localized corrosion and to perform quantitative analysis of the exchanged charge during the single-pit propagation.
Figure 1: Current potential curve and EIS diagrams measured at different potential for describing the passive film formation on Cantor alloy in chloride containing sulfuric acid solution.

Figure 1
3D Impedance Analysis on Dissolution Behavior of Additive-Manufactured Al-12%Si Alloy
Authors: Hoshi Yoshinao , Miyazawa Ryo , Otani Yuki , Takata Naoki , Kobashi Makoto 
Published: September 2023

Laser Powder Bed Fusion (LBPF) is one of the additive manufacturing techniques using a laser beam to melt and fuse layers of metal powder particles forming various metal products with complex shapes. Because the Al-Si alloy manufactured by LPBF has good mechanical properties compared to conventionally cast Al alloys, it is important to investigate the dissolution behavior of Al-Si alloy manufactured by LPBF for wider usage in industry.
In the present study, the film resistance of oxide film formed on additive-manufactured Al-12%Si alloys were investigated by a three-dimensional(3D) impedance spectroscopy1-5. This method allows for the estimation of the film resistance with time information because the impedance is plotted on the 3D diagram whose axes are real, imaginary and time, namely, the instantaneous impedance at arbitrary time can be determined from 3D impedance. To investigate the dissolution behavior of additive-manufactured Al alloys, the non-annealed sample (Al-12Si) and annealed samples at different temperatures ranging from 200 to 350 ℃ (Al-12Si300) and 530 ℃ (Al-12Si530) with arbitrary holding time were used for the electrochemical measurements. The 3D impedance of Al-12Si, Al-12Si300 and Al-12Si530 could be successively measured in the immersion conditions. The 3D impedance of Al-12Si and Al-12Si300 demonstrated that the impedance of both samples was increased with time. The 3D impedance of Al-12Si530 indicated small values during measurement. These results imply that the increase of impedance of Al-12Si and Al-12Si300 is associated with the formation of oxide film on the surface. The film resistance estimated from impedance spectra determined from 3D impedance and the morphology of samples after the measurement were correlated discussed.
References:

Z. B. Stoynov and B. S. Savova-Stoynov, J. Electroanal. Chem., 183 (1985) 133.

M. Itagaki et al., J. Power Sources, 135 (2004) 55.

M. Itagaki et al., J
.
Electroanal
.
Chem. 737 (2015) 78.

Y. Hoshi et al., J. Surf. Finish. Soc. Jpn., 67 (2016) 494.

H. Watanabe et al., J. Power Sources, 507 (2021) 230258.
Localized Corrosion and Passive Film Characteristics of Additive Vs. Wrought Al-Zn-Mg-Cu-Based Alloy
Authors: Rajendran Rupesh , Eisenhaure Jeffrey D , Kinsey Alex H , Singh Preet M 
Published: September 2023

Al-Zn-Mg-Cu alloys of the 7xxx series have proven to be excellent candidates for the aerospace, defense, and automotive industries due to their high strength to weight ratio, high corrosion resistance, and fatigue performance. For additively manufactured alloys manufactured using laser powder bed fusion (LPBF), the non-conventional microstructures formed as a result of one or more factors like alloy modification, LPBF process, and subsequent thermal treatments can lead to change in corrosion behavior and mechanisms.
Using scanning vibrating electrode technique (SVET) and immersion tests in chloride environments, this work concentrates on understanding the localized corrosion behavior of additively manufactured Al-Zn-Mg-Cu based alloy in comparison with its wrought counterpart. To understand the corrosion mechanisms, microstructures including the precipitates are characterized at different length scales using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and correlated with the corrosion behavior. The difference in passive film characteristics of additive vs. wrought Al-Zn-Mg-Cu based alloy is studied using electrochemical impedance spectroscopy (EIS) and X-Ray photoelectron spectroscopy (XPS) characterization. Overall, the LPBF-based alloy studied shows better corrosion performance than the wrought counterpart in chloride environments. The microstructural differences and mechanisms responsible for this behavior is proposed.
Kinetic Analysis on Hydrogen Entry into Steel in Aqueous Solutions by Alternating Current Method
Authors: Itagaki Masayuki , Okamoto Nana , Watanabe Hikari , Shitanda Isao 
Published: September 2023

Degradation of steels due to the hydrogen embrittlement, which is related to the hydrogen penetration reaction (HPR) into steel, is a serious problem from the standpoint of infrastructure preservation. A Devanathan-Stachurski permeation technique [1, 2] is a well-known method to determine a hydrogen penetration rate in metals. In this technique, two independent electrochemical cells are arranged on right across two surfaces of thin metal sheet and anodic and cathodic polarizations can be performed with each cell using the three-electrode system. The hydrogen penetration rate can be evaluated by measuring the oxidation current of hydrogen atoms diffused in the metal sheet at the anode side. The electrochemical impedance spectroscopy (EIS) was used for electrochemical measurement with the Devanathan cell to investigate HPR mechanisms because the time constants of hydrogen evolution and entry can be discriminated [3-5]. In this study, we used a complex hydrogen penetration ratio (CHPR), which is a transfer function related to hydrogen entry and diffusion in metal sheet, with the Devanathan cell to investigate kinetics of hydrogen entry into metals. The CHPRs of carbon steel sheet immersed in aqueous solution of different pH’s were measured in this study. The rate constant of hydrogen entry was determined by comparing experimental results with the simulated ones according to the theoretical equation, and influence of pH on hydrogen entry was discussed.
References:
[1] M. A. V. Devanathan and Z. Stachurski, Proc. R. Soc. Lond. Ser. A, 270, 90 (1962).
[2] M. A. Devanathan and Z. Stachurski, J. Electrochem. Soc., 111, 619 (1964).
[3] C. Gabrielli, P. P. Grand, A. Lasia, and H. Perrot, J. Electrochem. Soc., 151, A1943 (2004).
[4] A. Tada, E. Nishikata, ISJ internatonal, 56, 424 (2016).
[5] K. Fushimi, M. Jin, T. Nakanishi, Y. Hasegawa, T. Kawano and M. Kimura, ECS Electrochem. Lett., 3, C21 (2014).
Localized Corrosion Behavior and the Relationship to the Second Phases in Biodegradable ZX21 Mg Alloy in Hanks' Balanced Salt Solution
Authors: Fan Chien-Wei , Chu Peng-Wei 
Published: September 2023

Mg alloys are considered promising biodegradable implant materials owing to their high activity, which makes Mg alloys degradable in the human body and can avoid second removal surgeries. Also, compared with other biodegradable implant materials, Mg alloy has a similar density and Young’s modulus to human bones, which minimizes the stress shielding effect. ZX series Mg alloys, which contain Zn and Ca, are designed to increase the alloy strength but maintain biocompatibility. However, even with all the advantages, the high degradation rate limits the clinical applications of ZX series Mg alloys. With fast degradation, not only the mechanical properties are affected, but also a large amount of hydrogen gas and hydroxide ions would accumulate around the implant in the patient. Therefore, it is essential to investigate the corrosion mechanism of the ZX series Mg alloys to mitigate the degradation rates.
Localized corrosion is one of the noticeable features in the corrosion process of ZX series Mg alloys, which is the main reason for the low corrosion resistance and high degradation rate of the alloy. However, the origin and detailed mechanism of the initiation and propagation of localized corrosion on ZX series Mg alloys are still unclear. The second phases, which contain Zn and Ca, play complex roles in the corrosion process owing to the inhomogeneous elemental distribution and different electrochemical potentials with respect to the Mg alloy matrix. Thus, this study aims to investigate the microstructure of the localized corrosion sites and the galvanic effects around the second phases in a ZX series Mg alloy.
In this study, an Mg-2 wt%Zn-1 wt%Ca (ZX21) alloy was prepared, and the localized corrosion behavior was investigated in a Hanks’ balanced salt solution (HBSS) at 37°C. By scanning electron microscope (SEM)/focused ion beam (FIB) cross-sectional observations, two kinds of second phases were identified in the ZX21 Mg alloy, one is enriched with Zn and the other is not. After immersion in HBSS, galvanic corrosion sites were found in the Mg alloy matrix next to the second phase enriched with Zn, while the Mg alloy matrix next to the second phase with lower Zn concentration was intact. Furthermore, the second phases in the ZX21 Mg alloy were found to hinder the propagation of localized corrosion. The complex roles of the second phases in the ZX21 Mg alloy on the localized corrosion behavior will be discussed based on electrochemical measurements and microstructure characterizations.

Figure 1
Probing the Corrosion Rates of Novel Titanium Substrates in a Simulated PEM Fuel Cell Environment
Authors: Yapell David , Alexander David , Borup Rod L. , Rockward Tommy 
Published: September 2023

Metallic bipolar plates are often used in proton exchange membrane fuel cells (PEMFCs) due to their facile manufacturing process, high electrical and thermal conductivity, and mechanical strength. [1] Titanium is particularly popular due to its corrosion-resistive properties which come from a naturally occurring passive oxide layer on its surface. However, the naturally occurring passive film cannot fully withstand the acidic environment of an operating PEMFC. And inherently, without this protective layer; corrosion will inevitably occur. [2] Thicker oxide layers can be formed on the surface by exposing the titanium to elevated temperatures in the presence of oxygen
In this study, the corrosion resistance of commercially pure titanium with thermally grown oxidation layers and titanium directly coated with a commercial sub-oxide coating was investigated. The corrosion resistance of the various samples was examined with potentiostatic and potentiodynamic tests in sulfuric acid solution at various temperatures to simulate PEMFC conditions. The samples were also subjected to a novel accelerated stress test to evaluate long term durability under fuel cell vehicle startup and shutdown conditions.
References
[1] Wu, S., Yang, W., Yan, H., Zuo, X., Cao, Z., Li, H., Shi, M., & Chen, H. (2021). A review of modified metal bipolar plates for proton exchange membrane fuel cells. In International Journal of Hydrogen Energy (Vol. 46, Issue 12).
[2] Yu, F., Wang, K., Cui, L., Wang, S., Hou, M., Xiong, F., Zou, R., Gao, P., Peng, H., & Liu, Z. (2022). Vertical-Graphene-Reinforced Titanium Alloy Bipolar Plates in Fuel Cells. Advanced Materials, 34(21).