bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Corrosion and Solidification Microstructure of Laser Powder Bed Fusion 316L Stainless Steel
Authors: Macatangay Duane Armell , Conrades Jenna , Brunner Keegan , Kelly Robert 
Published: December 2020

The recent growth in additive manufacturing (AM) has fueled the motivation to understand the properties and performance of conventional alloys that have been synthesized through these methods. Laser powder bed fusion (LPBF) is a form of AM that uses high energy lasers to construct bulk materials from the melting and rapid solidification of powder on a layer-by-layer basis. While there has been considerable work done to optimize LPBF processing parameters for various metallic alloys and characterize the resulting microstructure and mechanical properties, little work has been performed to characterize the corrosion properties of these 3-D printed alloys.
316L is an austenitic stainless steel that is utilized in various applications due to its excellent mechanical properties and corrosion resistance. Although wrought 316L has a signature microstructure that is nominally single phase and made up of equiaxed grains, the additive process introduces a non-equilibrium microstructure. This leads to the introduction of compositional heterogeneities via melt pool boundaries and cellular structures and provide an origin for selective corrosion, leading to potential issues involving the longevity of these alloys in the as-printed state.
Sensitization occurs in stainless steels through the intergranular precipitation of chromium carbides at grain boundaries when the material is exposed to temperature ranges of 450 – 800 °C. This leads to the depletion of chromium at regions adjacent to grain boundaries and may lead to intergranular corrosion and intergranular stress corrosion cracking. The utilization of post-processing methods such as hot isotactic pressing induces temperatures within this range and may initiate this solid-solid phase transformation. The observation of accelerated sensitization in LPBF 316L provides motivation to characterize and understand this sensitization behavior.
This study explores corrosion in LPBF 316L with attention to melt pool boundary dissolution and intergranular corrosion. This study also acknowledges the effect of processing parameters on the resulting microstructure and corrosion behavior. Galvanostatic etching and potentiodynamic polarization are performed to quantify and understand the electrochemical behavior of these alloys. Characterization methods such as scanning electron microscopy and white light interferometry are used to probe the microstructure and corrosion morphology of these alloys in comparison to the conventionally wrought counterpart.
Ordered Macroporous Photonic Crystal Hot Electron Plasmonic Photocatalysts
Authors: Collins Gillian , Lonergan Alex , McNulty David , Glynn Colm , Buckley Darragh , Hu Changyu , O'Dwyer Colm 
Published: December 2020

Plasmon-enhanced photocatalysis provides opportunities for controlling chemical reaction rates, especially when the influence of the light is to enhance or alter charge transfer properties. Semiconductor photocatalysts with an inverse opal or photonic crystal structure not only provide large, open and accessible surface area, they are electrically interconnected as a porous network. This becomes a useful scaffold to dock metallic nanoparticles whose size can be tuned to absorb specific frequencies resonant with their localised surface plasmon resonance. Coupling this with the nature of the metal-semiconductor band structure (where the metal oxide is wide band gap) and exploiting certain properties of photonic crystals, more efficient photocatalysts are possible. We demonstrate semiconducting photonic crystal plasmonic photocatalysts using V2O5 and TiO2 as visible light semiconductor catalysts that showed superior performance to a conventional TiO2 support for hydrogenation of 4-nitrophenol. The approach married the photonic band gap, metal oxide semiconductor bandgap, slow photon effect and localised surface plasmon polaritons to maximum photon absorption to modulate charge transfer and electron density either in the metal nanoparticle, or the conduction band of the semiconductor to give a better photocatalyst.

References

[1] S. Linic, U. Aslam, C. Boerigter, M. Morabito, Nat. Mater.
14, 567 (2015)
[2] S. Linic, P. Christopher, D. B. Ingram, Nat. Mater.
10, 911 (2011)
[3] G. Collins, A. Lonergan, D. McNulty, C. Glynn, D. Buckley, C. Hu, and C. O’Dwyer, Adv. Mater. Interfaces.
7, 1901805 (2020).
[4] E. Armstrong, C. O’Dwyer, J. Mater. Chem. C
3, 6109 (2015)
[5] C. O’Dwyer, Adv. Mater.
28, 5681 (2016)
[6] T. Baba, Nat. Photon.
2, 465 (2008)
[7] G. Collins, E. Armstrong, D. McNulty, S. O’Hanlon, H. Geaney, C. O’Dwyer, Sci. Technol. Adv. Mater.
17, 563 (2016)
[8] A. Lonergan, D. McNulty, C. O’Dwyer, J. Appl. Phys.
124, 095106 (2018)
[9] G. Collins, M. Blomker, M. Osaik, J. D. Holmes, M. Bredol, C. O’Dwyer, Chem. Mater.
25, 4312 (2013)
[10] J. Liu, H. Zhao, M. Wu, B. Van der Schueren, Y. Li, O. Deparis, J. H. Ye, G. A. Ozin, T. Hasan, B. L. Su, Adv. Mater. 29, 1605349 (2017)
[11] S. O’Hanlon, D. McNulty, C. O’Dwyer, J. Electrochem. Soc.
164, D111 (2017)
[12] D. McNulty, E. Carroll, C. O’Dwyer, Adv. Energy Mater. 7, 1602291 (2017)

Figure 1. V2O5 3D macroporous inverse opal photonic crystal decorated with Au nanoparticles.

Figure 1
(Invited) Porous Structure Produced By Metal-Assisted Etching of Silicon
Authors: Yae Shinji , Matsumoto Ayumu 
Published: December 2020

Metal-assisted etching of silicon can produce porous silicon and silicon nanowires by simply immersing metal-modified silicon in a hydrofluoric acid solution without electrical bias [1]. Such etching proceeds by a local galvanic cell mechanism consisting of local anodic dissolution of silicon and local cathodic reduction of an oxidizing agent, such as oxygen [2, 3] or hydrogen peroxide, on catalytic metal. The structure of porous silicon is widely controlled from nanometer to sub-millimeter scale in pore size and from straight to an ants’ nest like in pore morphology by changing etching conditions [1-3]. We fabricate various porous structures on silicon wafers, and apply them to antireflection of solar cells and autocatalytic electroless formation of metal-nanorods and metal films on silicon surfaces. The structure of porous silicon is easily controlled in the nanometer scale with changing etching conditions such as kind, size, and distribution of metal catalysts, kind and concentration of oxidizing agent, intensity of photoillumination, and etching time. Recently, we found that general corrosion occurred on the top surface of the silicon substrate around the metal particles even under the dark condition [4]. The general corrosion depended on the metal species and it was explained by the formation and dissolution of a mesoporous layer.
[1] Z. Huang, N. Geyer, P. Werner, and U. Gösele, Adv. Mater., 23, 285 (2011).
[2] S. Yae, Y. Kawamoto, H. Tanaka, N. Fukumuro, and H. Matsuda, Electrochem. Comm., 5, 632 (2003).
[3] S. Yae, M. Tashiro, M. Abe, N. Fukumuro, H. Matsuda, J. Electrochem. Soc., 157, D90 (2010).
[4] A. Matsumoto, H. Son, M. Eguchi, K. Iwamoto, Y. Shimada, K. Furukawa, and S. Yae, RSC Adv., 10, 253 (2020).
(Invited) Anodization of Al in Neutral Oxalate Solution to Form Fine Nanoporous Film
Authors: Nishio Kazuyuki 
Published: December 2020

Anodic porous alumina has been widely used as an oxide coating of Al surfaces. Recently, fine and deep nanoporous structures are studied for use as novel templates in various applications. Highly ordered porous alumina is obtained by long-time anodization under appropriate conditions. Typically, hexagonally arranged nanopores with an interpore distance of 100 nm are formed in oxalic acid at 40 V.1 Here, we describe the formation of finer porous alumina (interpore distance of ~25 nm) by anodization in a potassium oxalate solution at 40 V. There have been a few reports on the formation of fine pores in boric acid and borate solutions under hot conditions.2-4 It is thought that the increase in the solubility of the oxide film in the hot borate electrolyte results in the growth of fine pores. However, in the case of anodization in a neutral oxalate solution, a fine nanoporous film was formed in a wide range of temperatures (0-85 °C).
Figure 1 (left) shows the results of Al anodization in 0.20 M potassium oxalate (pH 7.6) at 40 V vs Hg/Hg2SO4 for 6 h at 25 °C. The current gradually increased to ~0.4 mAcm-2 in 40 min then gradually decreased. After anodization for 2 h, the current reached a low value and remained at ~0.1 mAcm-2. As shown in the figure, the voltage between the working and counter electrodes remained at 41.7 V. Figure 2 (right) shows a cross-sectional SEM image of the obtained oxide film. Since the interpore distance of anodic porous alumina formed in conventional oxalic acid at 40 V is 100 nm (scale length in Fig. 2), the image clearly indicates that the pores are unusually fine. It is also confirmed that the oxide film is composed of following three layers: an upper porous layer that contains large pores, a lower porous layer with fine and straight pores and a flat barrier layer with a thickness of ~60 nm. The total thickness of the oxide film was 440 nm. It was also confirmed that the growth of nanopores terminates when the anodic current decreases from its peak to a low value.5

References
(1) H. Masuda, K Fukuda, Science, 268, 1466 (1995).
(2) G. A. Dorsey Jr., J. Electrochem. Soc.
1969, 116, 466.
(3) J. S. L. Leach, P. Neufeld, Corros. Sci.
1969, 9, 413.
(4) H. Takahashi, M. Nagayama, Electrochim. Acta
1978, 23, 279.
(5) K. Nishio, R. Sasaki, Chem. Lett., 2019, 48, 1126.

Figure 1
Similarity and Difference in the Plating Pretreatment for Mg and Al Alloys
Authors: Azumi Kazuhisa , Ikeda Kazuki , Watanabe Junpei , Yamamoto Hiroyuki 
Published: December 2020

Mg and Al are light-weight less-noble metals and are expected as a key material for potential applications in the fields of transportation to save energy. Especially for Mg alloys, the addition of corrosion resistance is essentially important for outside use. Plating has been used to provide various functionalities to metals such as good appearance, wear resistance, sliding performance, wettability or repellency, and corrosion resistance. Both Mg and Al have similar difficulty in the plating process because the surface of metals is always covered with the passive film (Al) or corrosion film (Mg) that prevents the plating process as the electron transfer and the metal-to-metal bonding. In the plating process, therefore, such surface films should be removed before or during the treatment process. The zincate pretreatment has been applied to these metals in which the surface was replaced with Zn layer that provides a good substrate for the subsequent plating process. In the zincate process, Al or Mg surface is dissolved, and Zn is deposited simultaneously by the substitution reaction in the zincate bath containing Zn(II) ions to cover the substrate. In the case of Al, this substitution reaction proceeds rapidly, and the substrate surface is almost completely covered with Zn layer. In the case of Mg, however, the coverage with Zn is more important than Al because Mg can be rapidly dissolved in the zincating bath. Excess dissolution of Mg substrate causes the undesired poor adhesion of the plating film to the substrate. Therefore, the zincating condition for Mg alloys should be optimized to take a balance between the Mg dissolution and the substitutional deposition of Zn.
On the other hand, a complicated structure composed of the area where dense pillars are formed and a bank surrounding this area is sometimes found on AZ31 alloy after the zincate treatment, as shown in Fig. 1. Such a structure is formed by the combination of the continuous dissolution of Mg substrate and the local deposition of Zn that protects Mg substrate from the dissolution. A bank is formed on the grain boundary of AZ31 surface, where initial Zn deposition preferentially proceeded. Such micro-structure can be compared with a well-known ordered porous alumina film formed on Al by the dynamic process of the continuous growth of anodic oxide film and mass transportation of ions in the growing film.

Figure 1
Modified Silicon Nanoparticles As an Anode for Lithium-Ion Batteries
Authors: Nurpeissova Arailym , Abilmazhinova Dana , Mukanova Aliya , Bakenov Zhumabay 
Published: December 2020

Due to the outstanding electrochemical properties, lithium-ion batteries have become a widely used energy storage technology for diverse types of devices. However, rapid progress in portable electronic devices and electric vehicles requires further essential improvement in the power and energy densities of lithium-ion batteries (LIBs) [1]. Conventional LIBs technology has reached the limit of its gravimetric / volumetric energy densities and power capabilities, reducing its ability to power new electronic devices and / or work as large batteries.
Among the promising candidates for anode materials, silicon (Si) has several advantages, including high theoretical capacity, low reaction potential against cathode material, environmental compatibility, low toxicity, and low cost. However, for the practical implementation of Si anodes in LIBs, it is necessary to consider one big critical issue: adaptation of large volume changes. Significant change in volume (4300%) during lithiation / delitration, leads to the volume expansion and grinding of Si particles, which leads to a rapid loss of electrode capacity, as shown in Figure 1a.
Figure 1. Schematic representation of volume expansion of Si anode (a) and suppression of volume expansion in modified Si anode (b)
This work presents the development of a new technology for the preparation of a composite anode material based on spinel Li4Ti5O12 (LTO) and Si with the addition of polyacrylonitrile (PAN) by liquid-phase coating, which demonstrates a synergistic positive effect on the performance of Si anodes (Fig. 1b). The idea lies in the coating the surface of silicon particles with LTO and PAN to suppress the volume expansion and improve the conductivity. The unique structure of LTO with zero deformation during lithiation / delitiation will help to withstand the volume change whereas PAN coating will improve the conductivity of the whole system.
Acknowledgements
This work was supported by projects AP05133706 “Innovative high-capacity anodes based on lithium titanate for a next generation of batteries” from the Ministry of Education and Science of the Republic of Kazakhstan and 091019CRP2114 “Three-Dimensional All Solid State Rechargeable Batteries” from Nazarbayev University.

References:

[1] J.M. Tarascon, M. Armand, Issues and challenges facing rechargeable lithium batteries, Nature. 414 (2001) 359–67. https://doi.org/10.1038/35104644

Figure 1
Characterization of Cathode/Electrolyte Interfacial Processes By Scanning Electrochemical Microscopy
Authors: Huang Di , Engtrakul Chaiwat , Nanayakkara Sanjini U. , Luo Hongmei , Tenent Robert 
Published: December 2020

Lithium transition metal oxides (LiMn2O4 and LiMO2 where M=Ni, Mn, Co, etc.) are widely applied in lithium ion batteries due to their considerable capacity and energy density. Multiple processes occurring at the cathode/electrolyte interface lead to performance degradation, one of which is the dissolution of transition metals. While transition metal dissolution has been known to occur for some time, open questions remain about mechanistic details of these processes. This work uses the scanning electrochemical microscope (SECM) to observe active cathode degradation processes in situ and immediately at the cathode/electrolyte interface. These results are also paired with complementary analysis employing inductively coupled plasma (ICP) and electron paramagnetic resonance (EPR) spectroscopies to yield insight into the properties of cathode degradation products and their reactivity.
This work focuses on studies of LiMn2O4 thin films as model cathodes and characterizes products of the Mn dissolution process. The degradation process of binder-free LiMn2O4 thin films prepared by polymer assisted deposition was investigated in varied electrolytes. The properties of Mn dissolution products from cathode degradation is compared to Mn salt solutions introduced into complementary electrolytes. Our results appear to indicate substantial variations between the properties of dissolved Mn salts and actual cathode degradation products. Moreover, electrolyte composition appears to affect the electrochemical behavior of metal dissolution products significantly. This likely indicates that the LiMn2O4 degradation mechanism in differing electrolytes undergo different degradation reaction pathways.
(Invited) Lessons Learnt and Challenges Ahead the Development of Ca-Based Batteries
Authors: Palacin M. 
Published: December 2020

The aim to develop batteries based in multivalent metal anodes has recently reemerged as part of the worldwide quest for new energy storage technologies with high energy density. Indeed, figures of merit attainable at the cell level computed using simple models indicate that the theoretical energy densities could easily top the state-of-the-art Li-ion, with costs being potentially much lower.
The viability of a rechargeable technology based on calcium has only been considered recently, after reversible plating/stripping in organic electrolytes was achieved. In the quest for suitable positive electrode materials for multivalent ions, both traditional intercalation hosts, such as TiS2 or V2O5, and alternative materials have been investigated. While V2O5 has so far attracted most attention, the interpretation of results is controversial, as changes in the diffraction pattern upon reduction might be related to the presence of water/protons in the electrolyte. Electrochemical extraction of calcium in Ca3Co2O6 is feasible but the only compound for which reversible electrochemical calcium insertion/extraction has reliably been shown to date is TiS2, despite the process being complex and non-practically viable as a result of solvent co-intercalation and high cell overpotential.
Overall, there is a long and winding road to follow before reliable proof-of-concept can be achieved and technological prospects evaluated. Development of reliable experimental setups, including reference and counter electrodes, coupled to complementary characterization techniques, as well as computational tools, is mandatory if steady progress is to be achieved.

Figure 1
(Keynote) Passivity at High Resolution: Insight from the Surface Science Approach
Authors: Maurice Vincent , Marcus Philippe 
Published: December 2020

Passivity is a key property for the durable use of metals and alloys since it provides nanometer-thick, long-term self-protection against corrosion thanks to the formation at the surface of a self-healing oxide film, the passive film. High resolution insight into the mechanisms of self‐protection against corrosion of metals and alloys by oxide passive films can be achieved with a surface science approach, applying surface analytical methods to model solid/liquid interfaces corroding under well‐controlled conditions. This will be illustrated by several examples drawn from the research work performed over the years in the research group led by Philippe Marcus. The review will cover the nucleation and growth of 2D passive layers of adsorbed hydroxide ions, the nanostructure and atomic structure of 3D passive films, the dissolution mechanisms of passivated surfaces and structural aspects of localized corrosion initiation at the nanometer and sub‐nanometer scales. Recent progress made on the understanding of the mechanisms governing chromium enrichment in passive films formed on Cr-bearing alloys such as stainless steel will be highlighted with data on nucleation and growth of the surface oxide obtained at both space and time high resolution.
Some of this research has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (ERC Advanced Grant No. 741123, Corrosion Initiation Mechanisms at the Nanometric and Atomic Scales: CIMNAS).
(Invited) Corrosion Kinetics and Pit Morphology of Pure Aluminum during Atmospheric Corrosion By in-Operando Microtomography
Authors: Melia Michael Anthony , Noell Philip , Schindelholz Eric John 
Published: December 2020

Predicting the kinetics and morphology of localized damage produced during corrosion of passive alloys is a foundational challenge in the development of robust damage models. This is especially the case for atmospheric corrosion, wherein the complex mechanistic interrelationships between environment, material microstructure, and the electrochemical processes driving corrosion are still little understood. This work shows the first results of long-term, in-situ characterization of atmospheric corrosion pits in commercially pure aluminum using x-ray microtomography to address the following questions: 1) how fast do individual pits in this material grow and what controls this growth rate? 2) how does the morphology of pits in this material evolve over time? 3) what is the relationship between pit morphology, the evolving electrolyte on the metal surface, and the microstructure? The mechanism involving the stifling of pit growth will also be discussed.
SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.
(Invited) Detection of Anodic Partial Current of Mg Dissolution by Gas-Chromatographic Analysis
Authors: Hoshi Yoshinao , Hirayama Yusuke , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki 
Published: December 2020

Magnesium (Mg) and its alloys are attractive materials as the battery electrodes, biomaterials and structural materials because they have high strength-to-weight ratios. However, they actively dissolve in aqueous solution and hydrogen evolution is observed. The hydrogen evolution rate of Mg is increased with increasing anodic polarization above the open circuit potential, which is commonly known as the negative difference effect1,2. The reaction mechanisms of this behavior are unknown and various kinds of electrochemical methods have been developed to clarify them4-7.
We have developed an in-situ detection method of hydrogen gas evolved from Mg during electrochemical measurement6. In this method, an electrochemical cell was connected to a gas chromatograph, namely, the hydrogen gas evolved from dissolving Mg is delivered to the gas chromatograph with the argon carrier gas during electrochemical measurement. The hydrogen evolution rate could be determined by calculating from the volume of hydrogen gas estimated by gas-chromatographic analysis. In our previous work6, the hydrogen evolution rate could be determined under potentiostatic polarization of Mg successively.
In the present study, we applied the developed method6 to the detection of anodic partial current of Mg dissolution. The cathodic current related to the hydrogen evolution reaction was estimated from the volume of hydrogen gas obtained by gas-chromatographic analysis during anodic polarization measurement of Mg. The partial anodic current at each polarization potential could be estimated by the sum of the measured anodic current and absolute value of cathodic current associated with the hydrogen evolution reaction, namely, the partial anodic polarization curve could be obtained by the plots of partial anodic current at each polarization potential. The characteristics of measured anodic polarization curve of Mg and partial anodic polarization curve obtained by the developed method were discussed.
References
1. G. Song, A. Atrens, D. St John, X. Wu and J. Nairn, Corros. Sci., 39, 1981 (1997).
2. G. S. Frankel, A. Samaniego and N. Birbilis, Corros. Sci., 70, 104 (2013).
3. M. Curioni, Electrochim. Acta, 120, 284 (2014).
4. S. Lebouil, A. Duboin, F. Monti, P. Tabeling, P. Volovitch and K. Ogle, Electrochim. Acta, 124, 176 (2014).
5. S. Fajardo and G. S. Frankel, Electrochim. Acta, 165, 255 (2015).
6. Y. Hoshi, R. Takemiya, I. Shitanda and M. Itagaki, J. Electrochem. Soc., 163, C303 (2016).
7. Y. Hoshi, K. Miyazawa, I. Shitanda and M. Itagaki, J. Electrochem. Soc., 165, C243 (2018).