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Quintero D, Matsuya H, Iwai M, Kitano S, Fushimi K, Habazaki H. Controlling Dielectric Film Defects to Increase the Breakdown Voltage of Conductive Polymer Solid Capacitors. ACS APPLIED MATERIALS & INTERFACES 2024; 16:1737-1748. [PMID: 38163250 DOI: 10.1021/acsami.3c14078] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Aluminum solid polymer capacitors are promising devices for the increased demand for power electronics applications. Nonetheless, the low breakdown voltage of commercially available catalysts (∼100 V) limits their applications. In this study, a hydroxide-film-covered high-purity aluminum was anodized at 700 V in boric acid at 85 °C, and the effect of a second hot water immersion (posthydration treatment) after anodizing on the breakdown voltage was studied as a possible future treatment to enhance the withstand voltages of solid electrolytic capacitors. The dielectric breakdown voltage of the anodized aluminum with a PEDOT:PSS coating was ∼500 V, being ∼200 V less than the anodizing voltage; however, the dielectric breakdown voltage was increased above 700 V by introducing the posthydration treatment due to the formation of a nanovoid layer above the dielectric alumina film. Our research suggests that the highly dispersed nanovoids incorporated with PEDOT:PSS avoid the current concentration at some local regions, effectively increasing the dielectric breakdown voltage. The posthydration treatment increased the leakage current by introducing physical defects in the dielectric film. However, the leakage current was reduced by a voltage sweep below the breakdown voltage after the PEDOT:PSS coating or a second anodizing process before the coating, keeping the breakdown voltage above 600 V. A promising processing route to obtain aluminum solid capacitors with high withstand voltage (600 V) found in our research is, first, dipping in hot water; second, anodizing at 700 V; then a second hot water treatment; and a second anodizing at 400 V, which keeps the capacitance invariable with a breakdown voltage enhanced.
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Affiliation(s)
- David Quintero
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Hisato Matsuya
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Mana Iwai
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Sho Kitano
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Koji Fushimi
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
| | - Hiroki Habazaki
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido 060-8628, Japan
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Gramatte S, Jeurgens LPH, Politano O, Simon Greminger JA, Baras F, Xomalis A, Turlo V. Atomistic Simulations of the Crystalline-to-Amorphous Transformation of γ-Al 2O 3 Nanoparticles: Delicate Interplay between Lattice Distortions, Stresses, and Space Charges. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:6301-6315. [PMID: 37097742 DOI: 10.1021/acs.langmuir.2c03292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The size-dependent phase stability of γ-Al2O3 was studied by large-scale molecular dynamics simulations over a wide temperature range from 300 to 900 K. For the γ-Al2O3 crystal, a bulk transformation to α-Al2O3 by an FCC-to-HCP transition of the O sublattice is still kinetically hindered at 900 K. However, local distortions of the FCC O-sublattice by the formation of quasi-octahedral Al local coordination spheres become thermally activated, as driven by the partial covalency of the Al-O bond. On the contrary, spherical γ-Al2O3 nanoparticles (NPs) (with sizes of 6 and 10 nm) undergo a crystalline-to-amorphous transformation at 900 K, which starts at the reconstructed surface and propagates into the core through collective displacements of anions and cations, resulting in the formation of 7- and 8-fold local coordination spheres of Al. In parallel, the reconstructed Al-enriched surface is separated from the stoichiometric core by a diffuse Al-depleted transition region. This compositional heterogeneity creates an imbalance of charges inside the NP, which induces a net attractive Coulombic force that is strong enough to reverse the initial stress state in the NP core from compressive to tensile. These findings disclose the delicate interplay between lattice distortions, stresses, and space-charge regions in oxide nanosystems. A fundamental explanation for the reported expansion of metal-oxide NPs with decreasing size is provided, which has significant implications for, e.g., heterogeneous catalysis, NP sintering, and additive manufacturing of NP-reinforced metal matrix composites.
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Affiliation(s)
- Simon Gramatte
- Laboratory for Advanced Materials Processing, Empa - Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, 3602 Thun, Switzerland
- Laboratory for Joining Technologies and Corrosion, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS-Université Bourgogne Franche-Comté, 9 Avenue A. Savary, Dijon F-91191, France
| | - Lars P H Jeurgens
- Laboratory for Joining Technologies and Corrosion, Empa - Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland
| | - Olivier Politano
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS-Université Bourgogne Franche-Comté, 9 Avenue A. Savary, Dijon F-91191, France
| | - Jose Antonio Simon Greminger
- Laboratory for Advanced Materials Processing, Empa - Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, 3602 Thun, Switzerland
| | - Florence Baras
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303, CNRS-Université Bourgogne Franche-Comté, 9 Avenue A. Savary, Dijon F-91191, France
| | - Angelos Xomalis
- Laboratory for Mechanics of Materials and Nanostructures, Empa - Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, 3602 Thun, Switzerland
| | - Vladyslav Turlo
- Laboratory for Advanced Materials Processing, Empa - Swiss Federal Laboratories for Materials Science and Technology, Feuerwerkerstrasse 39, 3602 Thun, Switzerland
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Sacco LN, Vollebregt S. Overview of Engineering Carbon Nanomaterials Such As Carbon Nanotubes (CNTs), Carbon Nanofibers (CNFs), Graphene and Nanodiamonds and Other Carbon Allotropes inside Porous Anodic Alumina (PAA) Templates. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:260. [PMID: 36678014 PMCID: PMC9861583 DOI: 10.3390/nano13020260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
The fabrication and design of carbon-based hierarchical structures with tailored nano-architectures have attracted the enormous attention of the materials science community due to their exceptional chemical and physical properties. The collective control of nano-objects, in terms of their dimensionality, orientation and size, is of paramount importance to expand the implementation of carbon nanomaterials across a large variety of applications. In this context, porous anodic alumina (PAA) has become an attractive template where the pore morphologies can be straightforwardly modulated. The synthesis of diverse carbon nanomaterials can be performed using PAA templates, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), and nanodiamonds, or can act as support for other carbon allotropes such as graphene and other carbon nanoforms. However, the successful growth of carbon nanomaterials within ordered PAA templates typically requires a series of stages involving the template fabrication, nanostructure growth and finally an etching or electrode metallization steps, which all encounter different challenges towards a nanodevice fabrication. The present review article describes the advantages and challenges associated with the fabrication of carbon materials in PAA based materials and aims to give a renewed momentum to this topic within the materials science community by providing an exhaustive overview of the current synthesis approaches and the most relevant applications based on PAA/Carbon nanostructures materials. Finally, the perspective and opportunities in the field are presented.
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Li Y, Morel A, Gallant D, Mauzeroll J. Controlling Surface Contact, Oxygen Transport, and Pitting of Surface Oxide via Single-Channel Scanning Electrochemical Cell Microscopy. Anal Chem 2022; 94:14603-14610. [PMID: 36214771 DOI: 10.1021/acs.analchem.2c02459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In single-channel scanning electrochemical cell microscopy, the applied potential during the approach of a micropipette to the substrate generates a transient current upon droplet contact with the substrate. Once the transient current exceeds a set threshold, the micropipette is automatically halted. Currently, the effect of the approach potential on the subsequent electrochemical measurements, such as the open-circuit potential and potentiodynamic polarization, is considered to be inconsequential. Herein, we demonstrate that the applied approach potential does impact the extent of probe-to-substrate interaction and subsequent microscale electrochemical measurements on aluminum alloy AA7075-T73.
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Affiliation(s)
- Yuanjiao Li
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, H3A 0B8 Quebec, Canada
| | - Alban Morel
- Automotive and Surface Transportation Research Centre, Division of Transportation and Manufacturing, National Research Council Canada, Aluminum Technology Center, 501 University Blvd East, Saguenay, G7H 8C3 Quebec, Canada
| | - Danick Gallant
- Automotive and Surface Transportation Research Centre, Division of Transportation and Manufacturing, National Research Council Canada, Aluminum Technology Center, 501 University Blvd East, Saguenay, G7H 8C3 Quebec, Canada
| | - Janine Mauzeroll
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, H3A 0B8 Quebec, Canada
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Di Quarto F, Zaffora A, Di Franco F, Santamaria M. A Generalized Semiempirical Approach to the Modeling of the Optical Band Gap of Ternary Al-(Ga, Nb, Ta, W) Oxides Containing Different Alumina Polymorphs. Inorg Chem 2021; 60:1419-1435. [PMID: 33471511 PMCID: PMC7877732 DOI: 10.1021/acs.inorgchem.0c02691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Indexed: 11/28/2022]
Abstract
A generalization of the modeling equation of optical band gap values for ternary oxides, as a function of cationic ratio composition, is carried out based on the semiempirical correlation between the differences in the electronegativity of oxygen and the average cationic electronegativity proposed some years ago. In this work, a novel approach is suggested to account for the differences in the band gap values of the different polymorphs of binary oxides as well as for ternary oxides existing in different crystalline structures. A preliminary test on the validity of the proposed modeling equations has been carried out by using the numerous experimental data pertaining to alumina and gallia polymorphs as well as the crystalline ternary Ga(1-x)AlxO3 polymorphs (α-Ga(1-x)AlxO3 and β-Ga(1-x)AlxO3) covering a large range of optical band gap values (4.50-8.50 eV). To make a more rigorous test of the modeling equation, we extended our investigation to amorphous ternary oxides anodically formed on Al-d-metal alloys (Al-Nb, Al-Ta, and Al-W) covering a large range of d-metal composition (xd-metal ≥ 0.2). In the last case, the novel approach allows one to overcome some difficulties experienced in fitting the optical band gap dependence from the Al-d-metal mixed anodic oxide composition as well as to provide a rationale for the departure, at the lowest d-metal content (xd-metal < 0.2), from the behavior observed for anodic films containing higher d-metal content.
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Affiliation(s)
- Francesco Di Quarto
- Dipartimento di Ingegneria, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | - Andrea Zaffora
- Dipartimento di Ingegneria, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | - Francesco Di Franco
- Dipartimento di Ingegneria, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
| | - Monica Santamaria
- Dipartimento di Ingegneria, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy
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Siol S, Mann J, Newman J, Miyayama T, Watanabe K, Schmutz P, Cancellieri C, Jeurgens LP. Concepts for chemical state analysis at constant probing depth by lab‐based XPS/HAXPES combining soft and hard X‐ray sources. SURF INTERFACE ANAL 2020. [DOI: 10.1002/sia.6790] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Sebastian Siol
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Joining Technologies and Corrosion Dübendorf Switzerland
| | - Jennifer Mann
- Physical Electronics Analytical Laboratory, Chanhassen MN USA
| | - John Newman
- Physical Electronics Analytical Laboratory, Chanhassen MN USA
| | | | | | - Patrik Schmutz
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Joining Technologies and Corrosion Dübendorf Switzerland
| | - Claudia Cancellieri
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Joining Technologies and Corrosion Dübendorf Switzerland
| | - Lars P.H. Jeurgens
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Joining Technologies and Corrosion Dübendorf Switzerland
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Sowa M, Parafiniuk M, Mouzêlo CM, Kazek-Kęsik A, Zhidkov IS, Kukharenko AI, Cholakh SO, Kurmaev EZ, Simka W. DC plasma electrolytic oxidation treatment of gum metal for dental implants. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.02.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Siol S, Beall C, Ott N, Döbeli M, González-Castaño M, Wick-Joliat R, Tilley SD, Jeurgens LPH, Schmutz P, Cancellieri C. Anodizing of Self-Passivating W xTi 1- x Precursors for W xTi 1- xO n Oxide Alloys with Tailored Stability. ACS APPLIED MATERIALS & INTERFACES 2019; 11:9510-9518. [PMID: 30734550 DOI: 10.1021/acsami.8b19170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
TiO2 and WO3 are two of the most important, industrially relevant earth-abundant oxides. Although both materials show complementary functionality and are promising candidates for similar types of applications such as catalysis, sensor technology, and energy conversion, their chemical stability in reactive environments differs remarkably. In this study, anodic barrier oxides are grown on solid-solution W xTi1- x alloy precursors covering a wide compositional range (0 ≤ x ≤ 1) with the goal of creating functional oxides with tailored stability. A strong Ti-cation enrichment in the surface region of the grown W xTi1- xO n layer is observed, which can be controlled by both the anodizing conditions and precursor composition. For Ti concentrations above 50 at. %, a continuous nanometer-thick TiO2 protective coating is achieved on top of a homogeneous W xTi1- xO n film as evidenced by X-ray photoelectron spectroscopy and transmission electron microscopy analyses. A comprehensive electrochemical assessment demonstrates a very stable passivation of the surface in both acidic and alkaline environments. This increase in chemical stability correlates directly with the presence of this protective TiO2 film. The results of this work provide insights into the oxidation behavior of W1- xTi x alloys, but more importantly demonstrate how controlled oxidation of self-passivating alloys can lead to oxide alloys with thin, protective surface layers that otherwise would require more sophisticated deposition methods.
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Affiliation(s)
- Sebastian Siol
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , 8600 Dübendorf , Switzerland
| | - Casey Beall
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , 8600 Dübendorf , Switzerland
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , 8057 Zurich , Switzerland
| | - Noémie Ott
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , 8600 Dübendorf , Switzerland
| | - Max Döbeli
- ETH Zurich, Ion Beam Physics , Otto-Stern-Weg 5 , 8093 Zurich , Switzerland
| | - Miriam González-Castaño
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , 8600 Dübendorf , Switzerland
| | - René Wick-Joliat
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , 8057 Zurich , Switzerland
| | - S David Tilley
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , 8057 Zurich , Switzerland
| | - Lars P H Jeurgens
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , 8600 Dübendorf , Switzerland
| | - Patrik Schmutz
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , 8600 Dübendorf , Switzerland
| | - Claudia Cancellieri
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , 8600 Dübendorf , Switzerland
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