bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Alumina Nanotubes Formed By Anodization of Aluminum Cast Alloy
Authors: Ono Sachiko , Hashimoto Hideki , Asoh Hidetaka 
Published: February 2020

Anodic porous alumina film, a typical self-ordered nanohole material formed by anodizing aluminum in an appropriate acidic solution, is used as a starting material of nanofabrication of functional devices besides a corrosion resistant surface oxide. In contrast to anodic titania nanotubes, anodic porous alumina is generally compact without spacing between the cell boundary. The tubular shape of anodic titania is suggested to be resulted in enrichment of fluoride between cells which is originated from electrolyte and more soluble than anodic titania. In the case of aluminum, it is reported that enrichment of only sulfate or ethylene glycol from electrolytes produces alumina nanotubes by anodization. In the present paper, the formation mechanisms of alumina nanotubes by anodization of Al cast alloy caused except the electrolyte origin will be discussed.
STEM image of vertical cross section prepared by ion-milling of the anodic film, which was formed on 99.99 % pure aluminum in oxalic acid at 160V, indicated close-packed hexagonal cell arrays with small voids of 15-20 nm at the triple cell points. Dark field STEM image clearly revealed a bright particle in the each void suggesting the presence of a heavy metal because of Z-contrast. By EDX point analysis, Cu enriched particles were found in the voids at the triple cell points. Nevertheless, in the case of anodic film formed at the similar condition on AC8A cast alloy including 0.97 % of Cu, tubular cells with the space of approximately 50 nm between cell boundary were formed unlike the case of pure aluminum including 60 ppm of Cu. Numerous branching of pores were also observed. EDX mapping revealed that Si was enriched in the outer layer of the cells and Cu was enriched at the area near the cell boundaries. Therefore, it is deduced that enrichment of Cu at the cell boundaries produces the tubular cells by accelerating oxide dissolution in addition to the electric breakdown accompanied by severe gas evolution that resulted in void formation at the triple cell points.
(Invited) Overview of Titania Nanotubes for Li-Ion Microbatteries
Authors: Djenizian Thierry 
Published: February 2020

Lithium-ion batteries (LIBs) are widely used to power portable devices, microelectronics, vehicles, etc. With many advantages such as high surface area and improved charge transport, self-supported 3-D nanostructured metal oxides such as titania nanotubes (TiO2nts) are promising electrode materials for LIBs and their impact is particularly significant when considering the miniaturization of energy storage systems and the development of 3D microbatteries.
This talk will review the concept and fabrication of all-solid-state Li-ion microbatteries using TiO2nts based based electrodes [1-7]. Effects of material selection and processing on the performance and reliability are presented as a means to develop conceptual guidelines to understand and improve microbattery designs. Fundamentals such as electrode reactions, lithium ion diffusion and the conformal electrodeposition mechanism of polymer electrolytes onto the nanostructured electrodes will be presented. The fabrication of a full 3D microcells showing high electrochemical performance will be presented and the development of the next generation of 3D FLEXIBLE microbatteries will be discussed.

REFERENCES

[1] B.L. Ellis, P. Knauth, T. Djenizian, Adv. Mater., 2014, 26, 3368.
[2] N. Plylahan, M. Letiche, M. Barr, T. Djenizian, Electrochem. Commun., 2014, 43, 121.
[3] N. Plylahan, A. Demoulin, C. Lebouin, P. Knauth, T. Djenizian, RSC Adv., 2015, 5, 28474.
[4] N. Plylahan, M. Letiche, M. Barr, B. Ellis, S. Maria, T. N. T. Phan, E. Bloch, P. Knauth, T. Djenizian,
J. Power Sources, 2015, 273, 1182.
[5] G. Salian, C. Lebouin, A. Demoulin, S. Maria, P. Knauth, M. Lepihin, A. Galeyeva, A. Kurbatov,
T. Djenizian, J. Power Sources, 2017, 340, 242.
[6] I. V. Ferrari, M. Braglia, T. Djenizian, P. Knauth, J. Power Sources, 2017, 353, 95.
[7] G. Salian, B. M. Koo, C. Lefevre, T. Cottineau, C. Lebouin, A. T. Tesfaye, P. Knauth, V. Keller,
T. Djenizian, Adv. Mater. Technol., DOI: 10.1002/admt.201700274, 2018.
Hard Porous Alumina Coatings Via Etidronic Acid Anodizing
Authors: Kikuchi Tatsuya , Takenaga Akimasa , Natsui Shungo , Suzuki Ryosuke O. 
Published: February 2020

Anodizing aluminum is very important for protecting the aluminum substrate, and anodizing in a sulfuric acid solution at low temperature causes the formation of hard porous alumina with a high Vickers hardness of more than Hv = 300. However, harder porous alumina is required to expand the applicability of porous alumina in various industrial applications. In the present investigation, we fabricated a hard porous alumina by aluminum anodizing in a new electrolyte, etidronic acid (1-hydroxyethane-1,1-diphosphonic acid, C2H8O7P2).
Highly pure aluminum plates (99.999 wt%) were electropolished in a 78 vol% CH3COOH/22 vol% 70%-HClO4 solution. The electropolished specimens were immersed in a 0.05–1.0 M etidronic acid solution (150 mL) at 278–308 K and then anodized at a constant voltage of 260 V or a constant-current density of 2.5–50 Am−
2 for up to 64 h. Two-step constant-voltage anodizing was also carried out for the fabrication of highly ordered porous alumina.
The electropolished specimens were anodized in etidronic acid solutions with various concentrations at various temperatures under the maximum current density condition without oxide burning. Figure 1 shows the changes in the Vickers hardness of the porous alumina, Hv, with changing concentration of the etidronic acid solution, c, at T
a = 278–308 K and i
a = 5–40 Am−2. Here, the thickness was adjusted to approximately 55 µm in each anodized specimen. The Vickers hardness decreased with increasing solution temperature for all concentrations. In addition, the Vickers hardness also decreased with increasing concentration at each solution temperature. This decrease is due to the chemical dissolution of porous alumina during anodizing. A hard porous alumina film measuring Hv = 610 can be fabricated by anodizing in a 0.05 M etidronic acid solution at 278 K and 5 Am−2.

Figure 1
Corrosion Behavior of Aluminum Alloys Deposited from Ionic Liquids
Authors: Böttcher René , Ispas Adriana , Bund Andreas 
Published: February 2020

Aluminum and its alloys have a wide range of applications due to their excellent properties, such as low density and high corrosion resistance. The electrochemical deposition of Al-based materials is not possible from aqueous solutions due to their rather negative Nernst potential (-1,66 V vs. SHE). There are few industrial processes for plating of aluminum, e.g. the SIGAL process. However, those processes usually are based on expensive, highly flammable and/or volatile substances, leading to high requirements regarding the technical equipment.
The deposition from ionic liquids (ILs) opens new possibilities for industrial processes. The ILs have large electrochemical windows (> 3 V) and permit high solubility for metal salts, allowing the electrochemical deposition of base metals, like aluminum, and a considerable number of its alloys. Furthermore, there is no hydrogen embrittlement of steel substrates in ILs due to their aprotic character, and the deposition of Al-based films is possible at room temperature.
Al-based materials are promising candidates for corrosion protection of steel and could replace environmentally harmful coatings, such as cadmium. ILs are still quite expensive, but their price continuously decreased during the last years, making an industrial process more interesting.
This paper will discuss recent results from the authors’ lab on the deposition of aluminum alloys from imidazolium based ILs. Binary alloys of aluminum with Zn, Sn and Cr were deposited and investigated. The deposition process regarding precursor concentration, process parameters, properties of the deposits (composition, structure, morphology) and corrosion behaviour in aqueous sodium chloride solution will be discussed. Furthermore, it will be shown that the pre-treatment of the used steel substrates plays a crucial role to obtain well adhering layers.
Characterization of Chromium Deposition from Trivalent Solutions By Eqcm and Near-Surface pH Measurements
Authors: Leimbach Martin , Tschaar Christoph , Schmidt Udo , Bund Andreas 
Published: February 2020

The demand for alternatives for chromic acid based electrolytes in chromium electroplating increases rapidly as the use of hexavalent chromium is restricted in serval countries [1]. In chromium plating for decorative applications, electrolyte formulations based on trivalent chromium are already known since several decades [2]. Especially solutions of chromium(III)-sulfate are promising candidates considering process management and quality of the deposits [3, 4]. However, chromium coatings plated from commercial chromium(III)-electrolytes cannot meet the requirements for decorative purposes completely yet. Especially deposition rate, corrosion resistance and color come short compared to layers made from chromic acid baths. In order to control these parameters, a profound knowledge of the deposition mechanism is crucial.
Electrochemical quartz crystal microbalance (EQCM) was used to study the mass-charge balance of the cathodic processes in chromium(III)-sulfate based plating baths. Current efficiency and deposition rate were determined as a function of time, additive concentration and current density. The addition of benzoic sulfimide (BSI) facilitates the reduction to chromium metal. An optimum current efficiency of 8.1 % was observed at 2.5 A dm-2 [5]. pH changes near the cathode surface during electroplating were evaluated in-situ by combining a pH electrode with a metal mesh and correlated with the results obtained by EQCM. Furthermore, the dependence of the color of the deposits on surface morphology was observed by SEM, AFM and colorimetry. The mechanism of metal growth appears to be different from chromic acid based systems since the grain size of the chromium depends on layer thickness.
[1] ECHA: Authorisation list, EC no. 215-607-8.
[2] Gianelos, L.: Plat Surf Finish
66 (1979) 5, 56-60.
[3] Handy, S. L.; Oduoza, C. F.; Pearson, T.: Trans IMF
84 (2006) 6, 300-308.
[4] Katirci, R.: Surf Eng
31 (2015) 6, 465-471.
[5] Leimbach, M.; Tschaar, C.; Schmidt, U.; Bund, A.: Electrochim Acta
270C (2018), 104-109.
The Role of Pitting at Mns Inclusions in Intergranular Corrosion of Sensitized Type 304 Stainless Steel in NaCl Solution
Authors: Ida Noriyuki , Muto Izumi , Sugawara Yu , Hara Nobuyoshi 
Published: February 2020

The degree of sensitization and susceptibility of intergranular corrosion of austenitic stainless steels are properly evaluated from immersion testing in acidic solutions as rapid screening methods. However, most of stainless steels are used in near-neutral pH environments, and the typical corrosion morphology in these environments is pitting. Acidification is known to occur inside pits due to the hydrolysis reaction of dissolving metal ions. Under practical service conditions around neutral pH such as seawater and river water, pitting is assumed to be closely related to the initiation of intergranular corrosion.
It is well-known that non-metallic inclusions, such as MnS, act as the initiation sites for pitting of stainless steels. Chiba et al. demonstrated that a small inclusion-free area on Type 304 indicated superior pitting corrosion resistance even in 3 M NaCl. 1) It would appear that MnS inclusions strongly affect pitting and intergranular corrosion of sensitized stainless steels.
To clarify the role of pitting at MnS inclusions in intergranular corrosion of sensitized Type 304 stainless steel (sensitized at 923 K), in situ observations were carried out during micro-scale anodic polarization in 1 M NaCl (pH 5.4). Micro-scale potentiodynamic anodic polarization was performed for a small area with a MnS inclusion at a sensitized grain boundary. Intergranular corrosion was initiated from the pit that was generated at the MnS inclusion located at the sensitized grain boundary. Acidification inside the pit probably caused intergranular corrosion due to the transition from passive to active state.
In 1 M NaCl, the depassivation pH values at the sensitized grain boundary with and without MnS inclusions were 1.0 and 0.4, respectively. It is likely that the dissolution of MnS accelerates the depassivation and promote the initiation pf intergranular corrosion. The dissolution products from MnS are supposed to accelerate depassivation of Cr-depleted regions.
1) A. Chiba, I. Muto, Y. Sugawara, N. Hara, J. Electrochem. Soc., 160, C511-C520 (2013).
Stress-Corrosion Behavior of Nickel Titanium Shape Memory Alloy Under Quasi-Static Loading
Authors: Mohajeri Mahdi , Haghgouyan Behrouz , Castaneda Homero , Lagoudas Dimitris 
Published: February 2020

Nickel titanium (NiTi) shape memory alloys (SMAs) are well known for their significant shape recovery under thermomechanical loading [1]. Austenitic SMA can recover its original shape upon unloading (pseudoelasticity) while martensitic SMA can do so after subsequent heating (shape memory effect). Understanding the corrosion behavior of NiTi SMAs is important for extending their successful applications. Studying the corrosion of SMAs is challenging due to the inherent complexity of their constitutive response together with the presence of different phases (austenite or martensite) and microstructural states (twinned or detwinned) [2].
In this study, the corrosion behavior of equiatomic NiTi under quasi-static loading in the plastic deformation regime is studied in artificial physiological solution at room temperature. Elelctrochemcial Frequencies Modulation (EFM) technique is used the parameters of which has been found in a previous study by the authors [3]. The corrosion parameters of NiTi are measured at different load levels during plastic deformation where the passive breakdown occurs. Strain distribution on the surface of the plastically deforming NiTi sample corresponding to these load levels is captured by means of Digital Image Correlation (DIC) technique [4]. Metal loss is measured using Faraday’s law and Open Circuit Potential (OCP) measurements show that the repassivation of oxide layer is not taken place. The findings are considered a step towards better understanding of the corrosion behavior of SMAs under thermo-mechanical loading.
References
[1] Lagoudas, D.C. ed., 2008. Shape memory alloys: modeling and engineering applications. Springer Science & Business Media.
[2] Mohajeri, M., Haghgouyan, B., Castaneda, H. and Lagoudas, D.C., 2018. Nickel Titanium Alloy failure analysis under thermal cycling and mechanical Loading: A Preliminary Study. arXiv preprint arXiv:1803.01110.
[3] Mohajeri, M., Castaneda, H. and Lagoudas, D.C., 2018, March. Corrosion monitoring of NiTi alloy with small-amplitude potential intermodulation technique. In Behavior and Mechanics of Multifunctional Materials and Composites XII (Vol. 10596, p. 1059616). International Society for Optics and Photonics.
[4] Haghgouyan, B., Shafaghi, N., Aydıner, C.C. and Anlas, G., 2016. Experimental and computational investigation of the effect of phase transformation on fracture parameters of an SMA. Smart Materials and Structures, 25(7), p.075010.
Anodic Current Density of Aluminum Oxide Film in Situ during Anodization of Aluminum by Fabry-Pérot Interferometry
Authors: Habib Khaled 
Published: February 2020

A combination of Fabry-Pérot interferometry and the DC electrochemical method have been used for the first time, in situ, to measure the anodic current density of aluminium oxide films in 0,6, and 10% sulfuric acid solutions (H2SO4). The calculated values of the anodic current density by Fabry-Pérot interferometry were verified by the DC electrochemical method and the electrochemical impedance spectroscopy (EIS). The corresponding thickness of the aluminum oxide film to the anodic current density was determined by Fabry-Pérot interferometry under a potentiolstatic potential of 9 V with respect to the open circuit potential of the aluminum samples in the H2SO4 solutions, for 90 minutes. The obtained thickness of the aluminum samples by Fabry-Pérot interferometry was verified by sanning electron microscopy(SEM) and compared to values that were obtained by the EIS. The calculated anodic current density by Fabry-Pérot interferometry was found in ageement with those of the DC electrochemical method. In contrast, the calculated anodic current density by Fabry-Pérot interferometry was found in a slight discrebancy with data obtained by the EIS.
Keywords. Aluminium, Aluminum oxide film, Fabry-Pérot interferometry, Electrochemical impedance spectroscopy (EIS), Anodic current density, and Sulfuric acid.
An Artificial Neural Networks for Electrochemical Impedance Spectroscopy of 304 Stainless Steel in Biodiesel
Authors: Rocabruno Valdés Carolin Ivette , Gonzalez Rodriguez Jose Gonzalo , Ramon Muñoz Ledo José Antonio , Hernández José Alfredo 
Published: February 2020

Biodiesel has been considered as a viable alternative fuel for transportation industry, as it demonstrated great potential in reducing the world dependence on fossil fuels and greenhouse gas emission. However, corrosion and a high susceptibility to oxidation or auto-oxidation are the main concerns associated with compatibility issues with metals and elastomers
On one hand, electrochemical impedance spectroscopy (EIS) is a powerful technique to characterize a wide variety of electrochemical systems, which allow us to evaluate the behavior at the electrode - electrolyte interface and helps in the interpretation of the corrosion mechanisms. This paper aims to develop an artificial neural network with the ability to learn from experimental values to predict EIS-Bode diagrams of 304 stainless steel in biodiesel. In this work, a feed-forward is proposed with three layers; composition of biodiesel divided in saturated, monounsaturated, and polyunsaturated methyl esters, blends biodiesel / diesel, Total acid number (TAN), exposure time, angular frequency, square root and square of angular frequency were considered as input variables on the model and the output layer contains two variables, impedance modulus and phase angle. The best fitting training data was acquired with 9-16-2 considering a Levenberg –Marquardt learning algorithm, a logarithmic sigmoid transfer function in the hidden and output layer. Experimental and simulated data were compared satisfactorily through a linear regression model with a correlation coefficient, R>0.98, mean square error, MSE < 9.13x10-4 in the validation stage and met the slope-intercept test with a confidence level of 99%. ANN model developed can be attractive to understand the synergy of the parameters and variables on corrosion behavior of metal in biodiesel besides to extract interest information related to phenomena.
Solution-Based Facile Fabrication of Heterojunction for Silicon Solar Cells Using Graphene Quantum Dots and PEDOT:PSS
Authors: Rongbin Xie , Noda Suguru 
Published: February 2020

Silicon remains the most widely employed material in solar cell due to the low cost, lack of toxicity, and small electronic band gap for near-infrared to visible light absorption. However, up to now, one of the main limitations of silicon solar cells is their high temperature and complex manufacturing processes. Recently, silicon solar cells hybridized with material like organic, semiconductor quantum dots, have attracted a great deal of research interest owing to their promise of room-temperature manufacturing and solution processing capability. But the problems of poor mobilities and toxicity need to be solved urgently. Fortunately, zero-dimensional graphene quantum dots (GQDs) have lately intrigued intensive interest in the field of energy and optoelectronic due to the tunable bandgap, emission in a range of visible light, longer hot carrier lifetimes, chemical stability and low toxicity. In addition to the low-cost and environment-friendly properties, GQDs could act as blocking layer to facilitate the separation of photo-generated electron-hole pairs and suppress the carrier recombination, thus increase the power conversion efficiency (PCE) in solar cells.
Here in, we present a solution-based, facile fabrication of silicon heterojunction solar cells using GQDs and poly(3,4-etyhlenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). The PEDOT:PSS/n-Si cell showed a PCE of 8.86%, and the application of GQDs to the PEDOT:PSS/n-Si interface enhanced the PCE to 10.24%. The passivation of n-Si surface by quick annealing in vacuum at 500 °C for 10 min enhanced the PCE further to 11.77%. The quick processes for heterojunction formation and surface passivation would be well suited for low-cost fabrication of solar cells based on crystalline Si thin films.
Cobalt-Iron-Manganese Electrodeposition for High Performance Magnetoelastic Resonators
Authors: Pillars Jamin R. , Langlois Eric D. , Arrington Christian L. , Monson Todd C. 
Published: February 2020

Magnetostrictive Co-Fe-Mn films were investigated for their use in fabricating magnetoelastic resonators. Electrodepositing these films enables batch fabrication of resonators with varying geometries and therefore, resonant frequencies, while controlling the film stoichiometry and crystallography. Boron, phosphorous, and molybdenum were used to increase the electrical resistivity and control film texture. Additionally, ascorbic acid and TMAB were used as “oxygen scavengers” to control the chemistry’s stability and limit the oxidation of the Fe2+ to Fe3+. As suggested by Osaka et al, Fe(OH)3 is formed and included into the film resulting in a decrease of the saturation magnetic flux density (Bs) value as the Fe cation is oxidized[1,2]. Additives, such as Saccharin and Sorbitol, were added as grain refiners and stress reducers, enabling flat cantilever structures that did not bend out of plain due to intrinsic stress gradients.
The composition and phase of the deposited films were controlled by temperature, agitation, concentrations in the electrodeposition chemistry, current density, and duty cycle of the pulsing regime. The samples were analyzed with EDS to determine the composition and XRD to look at film texture. Magnetic testing was performed using super conducting quantum interference device (SQUID) magnetometry, as well as visual inspection of the displacement on a deposit stress analyzer as a magnetic field was applied to the films. The magnetostriction was then correlated to EDS and XRD results to identify phase, stoichiometry and the plating parameters to produce improved magnetostriction while maintaining low intrinsic stress. Annealing studies of these films were performed using a tube furnace with inert gas to heat past the Curie temperature and then cool in the presence of an applied magnetic field. The applied magnetic field direction and its correlation with magnetic properties and phase will be discussed.

Acknowledgement

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

References

Osaka, T., et al., A high moment CoFe soft magnetic thin film prepared by electrodeposition. Electrochemical and Solid State Letters, 2003. 6(4): p. C53-C55.

Elhalawaty, S., et al., Oxygen Incorporation into Electrodeposited CoFe Films: Consequences for Structure and Magnetic Properties. Journal of the Electrochemical Society, 2011. 158(11): p. D641-D646.