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López-Galán OA, Boll T, Nogan J, Chassaing D, Welle A, Heilmaier M, Ramos M. One-step sputtering of MoSSe metastable phase as thin film and predicted thermodynamic stability by computational methods. Sci Rep 2024; 14:7104. [PMID: 38531954 DOI: 10.1038/s41598-024-57243-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 03/15/2024] [Indexed: 03/28/2024] Open
Abstract
We present the fabrication of a MoS2-xSex thin film from a co-sputtering process using MoS2 and MoSe2 commercial targets with 99.9% purity. The sputtering of the MoS2 and MoSe2 was carried out using a straight and low-cost magnetron radio frequency sputtering recipe to achieve a MoS2-xSex phase with x = 1 and sharp interface formation as confirmed by Raman spectroscopy, time-of-flight secondary ion mass spectroscopy, and cross-sectional scanning electron microscopy. The sulfur and selenium atoms prefer to distribute randomly at the octahedral geometry of molybdenum inside the MoS2-xSex thin film, indicated by a blue shift in the A1g and E1g vibrational modes at 355 cm-1 and 255 cm-1, respectively. This work is complemented by computing the thermodynamic stability of a MoS2-xSex phase whereby density functional theory up to a maximum selenium concentration of 33.33 at.% in both a Janus-like and random distribution. Although the Janus-like and the random structures are in the same metastable state, the Janus-like structure is hindered by an energy barrier below selenium concentrations of 8 at.%. This research highlights the potential of transition metal dichalcogenides in mixed phases and the need for further exploration employing low-energy, large-scale methods to improve the materials' fabrication and target latent applications of such structures.
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Affiliation(s)
- Oscar A López-Galán
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
- Institute for Applied Materials and Materials Science (IAM-WK), Karlsruhe Institute of Technology (KIT), Engelbert-Arnold-Str. 4, 76131, Karlsruhe, Germany.
- Departamento de Física y Matemáticas, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Avenida del Charro #450 N, Ciudad Juárez, 32310, CHIH, México.
| | - Torben Boll
- Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - John Nogan
- Sandia National Laboratories, Center for Integrated Nanotechnologies (CINT), 1101 Eubank Bldg. SE, Albuquerque, NM, 87110, USA
| | - Delphine Chassaing
- Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Alexander Welle
- Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
- Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Martin Heilmaier
- Institute for Applied Materials and Materials Science (IAM-WK), Karlsruhe Institute of Technology (KIT), Engelbert-Arnold-Str. 4, 76131, Karlsruhe, Germany
| | - Manuel Ramos
- Departamento de Física y Matemáticas, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Avenida del Charro #450 N, Ciudad Juárez, 32310, CHIH, México.
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Bayoumy D, Boll T, Karapuzha AS, Wu X, Zhu Y, Huang A. Effective Platform Heating for Laser Powder Bed Fusion of an Al-Mn-Sc-Based Alloy. Materials (Basel) 2023; 16:7586. [PMID: 38138728 PMCID: PMC10744844 DOI: 10.3390/ma16247586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023]
Abstract
Platform heating is one of the effective strategies used in laser powder bed fusion (LPBF) to avoid cracking during manufacturing, especially when building relatively large-size components, as it removes significant process-induced residual strains. In this work, we propose a novel and simple method to spare the elaborate post-processing heat treatment typically needed for LPBF Al-Sc alloys without compromising the mechanical properties. We systematically investigated the effects of LPBF platform heating at 200 °C on the residual stress relief, microstructure, and mechanical performance of a high-strength Al-Mn-Sc alloy. The results reveal that LPBF platform heating at 200 °C is sufficient to largely relieve the process-induced residual stresses compared to parts built on an unheated 35 °C platform. Meanwhile, the platform heating triggered the dynamic precipitation of uniformly dispersed (1.5-2 nm) Sc-rich nano-clusters. Their formation in a high number density (1.75 × 1024 m-3) resulted in a ~20% improvement in tensile yield strength (522 MPa) compared to the build on the unheated platform, without sacrificing the ductility (up to 18%). The improved mechanical properties imply that platform heating at 200 °C can strengthen the LPBF-synthesised Sc-containing Al alloys via in situ aging, which is further justified by an in situ measurement study revealing that the developing temperatures in the LPBF part are within the aging temperature range of Al-Sc alloys. Without any post-LPBF treatments, these mechanical properties have proven better than those of most Al-Sc alloys through long-time post-LPBF heat treatment.
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Affiliation(s)
- Dina Bayoumy
- Monash Centre for Additive Manufacturing, 15–17 Normanby Rd, Notting Hill, VIC 3168, Australia; (D.B.); (A.S.K.); (X.W.)
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Torben Boll
- Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany;
| | - Amal Shaji Karapuzha
- Monash Centre for Additive Manufacturing, 15–17 Normanby Rd, Notting Hill, VIC 3168, Australia; (D.B.); (A.S.K.); (X.W.)
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Xinhua Wu
- Monash Centre for Additive Manufacturing, 15–17 Normanby Rd, Notting Hill, VIC 3168, Australia; (D.B.); (A.S.K.); (X.W.)
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Yuman Zhu
- Monash Centre for Additive Manufacturing, 15–17 Normanby Rd, Notting Hill, VIC 3168, Australia; (D.B.); (A.S.K.); (X.W.)
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Aijun Huang
- Monash Centre for Additive Manufacturing, 15–17 Normanby Rd, Notting Hill, VIC 3168, Australia; (D.B.); (A.S.K.); (X.W.)
- Department of Materials Science and Engineering, Monash University, Clayton, VIC 3800, Australia
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Pantenburg I, Cronau M, Boll T, Duncker A, Roling B. Challenging Prevalent Solid Electrolyte Interphase (SEI) Models: An Atom Probe Tomography Study on a Commercial Graphite Electrode. ACS Nano 2023; 17:21531-21538. [PMID: 37902648 DOI: 10.1021/acsnano.3c06560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
Lithium-ion batteries (LIBs) are the dominating energy storage technology for electric vehicles and portable electronic devices. Since the resources of raw materials for LIBs are limited and recycling technologies for LIBs are still under development, improvements in the long-term stability of LIBs are of paramount importance and, in addition, would lead to a reduction in the levelized cost of storage (LCOS). A crucial limiting factor is the aging of the solid electrolyte interphase (SEI) on the active material particles in the anode. Here, we demonstrate the potential of atom probe tomography for elucidating the complex mosaic-type structure of the SEI in a graphite composite anode. Our 3D reconstruction shows unseen details and reveals the existence of an apolar organic microphase pervading the SEI over its entire thickness. This finding is in stark contrast to the prevalent two-layer SEI model, in which organic compounds are the dominating species only in the outer SEI layer being in contact with the liquid electrolyte. The observed spatial arrangement of the apolar organic microphase promises a better understanding of the passivation capability of the SEI, which is necessary to expand the battery lifetime.
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Affiliation(s)
- Isabel Pantenburg
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Marvin Cronau
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Torben Boll
- Institute for Applied Materials (IAM-WK), Institute for Nanotechnology (INT), and Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Building 695, 76344 Eggenstein-Leopoldshafen, Germany
| | - Annalena Duncker
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
| | - Bernhard Roling
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany
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Pineda-Domínguez PM, Boll T, Nogan J, Heilmaier M, Hurtado-Macías A, Ramos M. The Piezoresponse in WO 3 Thin Films Due to N 2-Filled Nanovoids Enrichment by Atom Probe Tomography. Materials (Basel) 2023; 16:1387. [PMID: 36837019 PMCID: PMC9960742 DOI: 10.3390/ma16041387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/02/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
Tungsten trioxide (WO3) is a versatile n-type semiconductor with outstanding chromogenic properties highly used to fabricate sensors and electrochromic devices. We present a comprehensive experimental study related to piezoresponse with piezoelectric coefficient d33 = 35 pmV-1 on WO3 thin films ~200 nm deposited using RF-sputtering onto alumina (Al2O3) substrate with post-deposit annealing treatment of 400 °C in a 3% H2/N2-forming gas environment. X-ray diffraction (XRD) confirms a mixture of orthorhombic and tetragonal phases of WO3 with domains with different polarization orientations and hysteresis behavior as observed by piezoresponse force microscopy (PFM). Furthermore, using atom probe tomography (APT), the microstructure reveals the formation of N2-filled nanovoids that acts as strain centers producing a local deformation of the WO3 lattice into a non-centrosymmetric structure, which is related to piezoresponse observations.
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Affiliation(s)
- Pamela M. Pineda-Domínguez
- Departamento de Física y Matemáticas, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Avenida del Charro 450 N, Cd. Juárez, Chihuahua 32310, Mexico
| | - Torben Boll
- Institut für Angewandte Materialien-Werkstoffkunde (IAM-WK), Karlsruhe Institute of Technology, Engelbert-Arnold-Strasse 4, 76131 Karlsruhe, Germany
- Karlsruhe Nano Micro Facility (KNMFi), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute for Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - John Nogan
- Center for Integrated Nanotechnologies, 1101 Eubank Bldg. SE, Albuquerque, NM 87110, USA
| | - Martin Heilmaier
- Institut für Angewandte Materialien-Werkstoffkunde (IAM-WK), Karlsruhe Institute of Technology, Engelbert-Arnold-Strasse 4, 76131 Karlsruhe, Germany
| | - Abel Hurtado-Macías
- Laboratorio Nacional de Nanotecnología, Centro de Investigación en Materiales Avanzados S.C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua 31109, Mexico
| | - Manuel Ramos
- Departamento de Física y Matemáticas, Instituto de Ingeniería y Tecnología, Universidad Autónoma de Ciudad Juárez, Avenida del Charro 450 N, Cd. Juárez, Chihuahua 32310, Mexico
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Kauffmann-Weiss S, Iida K, Tarantini C, Boll T, Schneider R, Ohmura T, Matsumoto T, Hatano T, Langer M, Meyer S, Jaroszynski J, Gerthsen D, Ikuta H, Holzapfel B, Hänisch J. Microscopic origin of highly enhanced current carrying capabilities of thin NdFeAs(O,F) films. Nanoscale Adv 2019; 1:3036-3048. [PMID: 36133600 PMCID: PMC9417295 DOI: 10.1039/c9na00147f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/03/2019] [Indexed: 06/16/2023]
Abstract
Fe-based superconductors present a large variety of compounds whose physical properties strongly depend on the crystal structure and chemical composition. Among them, the so-called 1111 compounds show the highest critical temperature T c in the bulk form. Here we demonstrate the realization of excellent superconducting properties in NdFeAs(O1-x F x ). We systematically investigated the correlation between the microstructure at the nanoscale and superconductivity in an epitaxial 22 nm NdFeAs(O1-x F x ) thin film on a MgO single crystalline substrate (T c = 44.7 K). Atomic resolution analysis of the microstructure by transmission electron microscopy and atom probe tomography identified several defects and other inhomogeneities at the nanoscale that can act as extrinsic pinning centers. X-Ray diffraction and transmission electron microscopy displayed a broad variation of the a-axis lattice parameter either due to a partially strained layer at the interface to the substrate, high local strain at dislocation arrays, mosaicity, or due to composition variation within the film. The electrical transport properties are substantially affected by intrinsic pinning and a matching field corresponding to the film thickness and associated with the Bean-Livingston surface barrier of the surfaces. The thin film showed a self-field critical current density J c(4.2 K) of ∼7.6 MA cm-2 and a record pinning force density of F p ≈ 1 TN m-3 near 35 T for H‖ab at 4.2 K. These investigations highlight the role of the microstructure in fine-tuning and possibly functionalizing the superconductivity of Fe-based superconductors.
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Affiliation(s)
- Sandra Kauffmann-Weiss
- Institute for Technical Physics (ITEP), Karlsruhe Institute of Technology (KIT) 76344 Eggenstein-Leopoldshafen Germany
| | - Kazumasa Iida
- Department of Materials Physics, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
- Department of Crystalline Materials Science, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
| | - Chiara Tarantini
- Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University 2031 East Paul Dirac Drive Tallahassee Florida 32310 USA
| | - Torben Boll
- Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT) 76344 Eggenstein-Leopoldshafen Germany
- Institute for Applied Materials (IAM-WK), Karlsruhe Institute of Technology (KIT) 76344 Karlsruhe Germany
| | - Reinhard Schneider
- Laboratory for Electron Microscopy (LEM), Karlsruhe Institute of Technology (KIT) Engesserstraße 7 76131 Karlsruhe Germany
| | - Taito Ohmura
- Department of Crystalline Materials Science, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
| | - Takuya Matsumoto
- Department of Materials Physics, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
| | - Takafumi Hatano
- Department of Materials Physics, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
- Department of Crystalline Materials Science, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
| | - Marco Langer
- Institute for Technical Physics (ITEP), Karlsruhe Institute of Technology (KIT) 76344 Eggenstein-Leopoldshafen Germany
| | - Sven Meyer
- Institute for Technical Physics (ITEP), Karlsruhe Institute of Technology (KIT) 76344 Eggenstein-Leopoldshafen Germany
| | - Jan Jaroszynski
- Applied Superconductivity Center, National High Magnetic Field Laboratory, Florida State University 2031 East Paul Dirac Drive Tallahassee Florida 32310 USA
| | - Dagmar Gerthsen
- Laboratory for Electron Microscopy (LEM), Karlsruhe Institute of Technology (KIT) Engesserstraße 7 76131 Karlsruhe Germany
| | - Hiroshi Ikuta
- Department of Materials Physics, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
- Department of Crystalline Materials Science, Nagoya University Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
| | - Bernhard Holzapfel
- Institute for Technical Physics (ITEP), Karlsruhe Institute of Technology (KIT) 76344 Eggenstein-Leopoldshafen Germany
| | - Jens Hänisch
- Institute for Technical Physics (ITEP), Karlsruhe Institute of Technology (KIT) 76344 Eggenstein-Leopoldshafen Germany
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Neibecker P, Leitner M, Kushaim M, Boll T, Anjum D, Al-Kassab T, Haider F. L1 2 ordering and δ' precipitation in Al-Cu-Li. Sci Rep 2017; 7:3254. [PMID: 28607382 PMCID: PMC5468256 DOI: 10.1038/s41598-017-03203-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/25/2017] [Indexed: 11/09/2022] Open
Abstract
The precipitation mechanism of the δ′ (Al3Li) phase in Al-Li alloys has been controversially discussed in recent decades, specifically with respect to a conjectured congruent ordering process. However, kinetics in the Al-Li system does not allow to resolve the intermediate stages of precipitation and hence to experimentally clarify this issue. In this paper, we are revisiting the subject in ternary Al-Cu-Li alloys with pronouncedly slower kinetics, employing Transmission Electron Microscopy, High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy, Differential Scanning Calorimetry and Atom Probe Tomography. The results show clear evidence for congruent ordering in a selected compositional range, revealing an already strongly L12 ordered microstructure after natural aging with a chemically homogeneous Li distribution and a decomposition of the alloy upon annealing at elevated temperatures. The presented study of the δ′ precipitation evaluates the reaction pathway of this process and compares it to the predictions of the Bragg-Williams-Gorsky model with respect to decomposition and ordering in this alloy system.
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Affiliation(s)
- Pascal Neibecker
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748, Garching, Germany. .,King Abdullah University of Science and Technology (KAUST), 23955-6900, Thuwal, Kingdom of Saudi Arabia. .,University of Augsburg, Department of Physics, Universitätsstr. 1, 86159, Augsburg, Germany.
| | - Michael Leitner
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, 85748, Garching, Germany
| | - Muna Kushaim
- King Abdullah University of Science and Technology (KAUST), 23955-6900, Thuwal, Kingdom of Saudi Arabia.,Taibah University, Faculty of Science, Department of Physics, PO Box 344, Al-Madinah, Kingdom of Saudi Arabia
| | - Torben Boll
- Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien - Werkstoffkunde (IAM-WK), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Dalaver Anjum
- King Abdullah University of Science and Technology (KAUST), Imaging and Characterization Lab, 23955-6900, Thuwal, Kingdom of Saudi Arabia
| | - Tala'at Al-Kassab
- King Abdullah University of Science and Technology (KAUST), 23955-6900, Thuwal, Kingdom of Saudi Arabia
| | - Ferdinand Haider
- University of Augsburg, Department of Physics, Universitätsstr. 1, 86159, Augsburg, Germany
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Boll T, Unocic KA, Pint BA, Stiller K. Interfaces in Oxides Formed on NiAlCr Doped with Y, Hf, Ti, and B. Microsc Microanal 2017; 23:396-403. [PMID: 28318469 DOI: 10.1017/s1431927617000186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This study applies atom probe tomography (APT) to analyze the oxide scales formed on model NiAlCr alloys doped with Hf, Y, Ti, and B. Due to its ability to measure small amounts of alloying elements in the oxide matrix and its ability to quantify segregation, the technique offers a possibility for detailed studies of the dopant's fate during high-temperature oxidation. Three model NiAlCr alloys with different additions of Hf, Y, Ti, and B were prepared and oxidized in O2 at 1,100°C for 100 h. All specimens showed an outer region consisting of different spinel oxides with relatively small grains and the protective Al2O3-oxide layer below. APT analyses focused mainly on this protective oxide layer. In all the investigated samples segregation of both Hf and Y to the oxide grain boundaries was observed and quantified. Neither B nor Ti were observed in the alumina grains or at the analyzed interfaces. The processes of formation of oxide scales and segregation of the alloying elements are discussed. The experimental challenges of the oxide analyses by APT are also addressed.
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Affiliation(s)
- Torben Boll
- 1Department of Physics,Chalmers University of Technology,SE-412 96 Göteborg,Sweden
| | - Kinga A Unocic
- 2Oak Ridge National Laboratory,Materials Science and Technology Division,Oak Ridge,TN 37831,USA
| | - Bruce A Pint
- 2Oak Ridge National Laboratory,Materials Science and Technology Division,Oak Ridge,TN 37831,USA
| | - Krystyna Stiller
- 1Department of Physics,Chalmers University of Technology,SE-412 96 Göteborg,Sweden
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Boll T, Thuvander M, Koch S, Wagner JN, Nedfors N, Jansson U, Stiller K. An APT investigation of an amorphous Cr-B-C thin film. Ultramicroscopy 2015; 159 Pt 2:217-22. [PMID: 25667171 DOI: 10.1016/j.ultramic.2015.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 12/07/2014] [Accepted: 01/05/2015] [Indexed: 11/26/2022]
Abstract
A magnetron sputtered amorphous Cr-B-C thin film was investigated by means of atom probe tomography (APT). The film is constituted of two phases; a Cr-rich phase present as a few nanometer large regions embedded in a Cr-poor phase (tissue phase). The Cr-rich regions form columnar chains oriented parallel to the growth direction of the film. It was found that the Cr-rich regions have a higher B:C ratio than the Cr-poor regions. The composition of the phases was determined as approximately 35Cr-33B-30C and 15Cr-40B-42C (at%), respectively. The results suggest that this type of nanocomposite films has a more complex structure than previously anticipated, which may have an importance for the mechanical and electrical properties.
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Affiliation(s)
- T Boll
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - M Thuvander
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
| | - S Koch
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - J N Wagner
- KNMF, Karslruhe Institute of Technology, DE-76344 Eggenstein-Leopoldshafen, Germany
| | - N Nedfors
- Department of Chemistry, The Ångström Laboratory, Uppsala University, SE-751 21 Uppsala, Sweden
| | - U Jansson
- Department of Chemistry, The Ångström Laboratory, Uppsala University, SE-751 21 Uppsala, Sweden
| | - K Stiller
- Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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Boll T, Zhu ZY, Al-Kassab T, Schwingenschlögl U. Atom probe tomography simulations and density functional theory calculations of bonding energies in Cu3Au. Microsc Microanal 2012; 18:964-970. [PMID: 23095446 DOI: 10.1017/s1431927612001365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this article the Cu-Au binding energy in Cu3Au is determined by comparing experimental atom probe tomography (APT) results to simulations. The resulting bonding energy is supported by density functional theory calculations. The APT simulations are based on the Müller-Schottky equation, which is modified to include different atomic neighborhoods and their characteristic bonds. The local environment is considered up to the fifth next nearest neighbors. To compare the experimental with simulated APT data, the AtomVicinity algorithm, which provides statistical information about the positions of the neighboring atoms, is applied. The quality of this information is influenced by the field evaporation behavior of the different species, which is connected to the bonding energies.
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Affiliation(s)
- Torben Boll
- Institut für Materialphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
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Abstract
Dual-phase TiAl/Ti3Al-alloys consisting of a lamellar structure, comprising gamma-phase plus a small amount of alpha2-phase, with addition of 1, 5 and 10at% Nb were prepared. The samples were investigated by means of field ion microscopy (FIM) and atom probe tomography (APT). The influence of doping elements on the variation of field evaporation and microstructural parameters in the gamma-phase as studied by FIM and APT will be reported in this contribution. The intermetallic gamma-Phase of TiAl exhibits a L1(0)-structure, which has alternating Ti- and Al-planes in the [001]-superstructure direction. Because of the significant difference in the evaporation field strengths of Ti and Al, it is usually not possible to directly distinguish Ti- and Al-planes in this direction in the APT data. Therefore, it is not possible to assign Nb to any plane, as well. To solve this problem an algorithm, using statistical methods, was developed, which allows to inherently distinguish the planes. A comparison of the results for [100]- and [001]-directions shows that Nb prefers Ti-sites. The sequence of field evaporation field strengths, which follows the trend E(Nb) > E(Al) > E(Ti), could also be deduced.
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Affiliation(s)
- T Boll
- Institut für Materialphysik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany.
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Al-Kassab T, Yuan Y, Kluthe C, Boll T, Liu ZG. Investigation of the ordering and atomic site occupancies of Nb-doped TiAl/Ti3Al intermetallics. SURF INTERFACE ANAL 2007. [DOI: 10.1002/sia.2530] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Abstract
BACKGROUND The treatment of displaced Colles-type fractures of the distal part of the radius remains a challenge. Two procedures for closed reduction and Kirschner wire osteosynthesis of these fractures were compared in a prospective randomized study. METHODS One hundred consecutive patients with a Colles fracture of the distal part of the radius (AO classification 23-A2, 23-A3, or 23-C1) were treated over an eighteen-month period. One group was managed with the conventional method, described by Willenegger and Guggenbuhl in 1959, in which two Kirschner wires are introduced into the styloid process of the radius. The other group was treated with the Kapandji method, as modified by Fritz et al., in which two Kirschner wires are inserted into the fracture gap and a third is placed through the styloid process. Postoperative care was standardized for both groups and carried out according to a strict procedure. Forty patients who had been operated on according to the modified Kapandji method and forty-one treated with the Willenegger technique were available for follow-up, for a follow-up rate of 81%. The follow-up assessment was performed with a modified version of the Martini score. RESULTS The median time to follow-up was ten months (range, six to twenty months). The results as assessed with the Martini score were, on the average, good to very good for the patients treated with the Kapandji method and satisfactory to good for the patients treated with the conventional Kirschner wire fixation. The duration of radiographic exposure was significantly shorter with the Kapandji method than with the Willenegger technique. CONCLUSIONS Conventional Kirschner wire fixation remains a good method of osteosynthesis for the treatment of displaced fractures of the distal part of the radius. We found both the functional and radiographic outcomes of the Kapandji method to be significantly better than those of the Willenegger technique. LEVEL OF EVIDENCE Therapeutic study, Level I-1a (randomized controlled trial [significant difference]). See Instructions to Authors for a complete description of levels of evidence.
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Affiliation(s)
- P C Strohm
- Städtisches Klinikum Karsluhe, Karsluhe, Germany.
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Vukicević S, Stavljenić A, Boll T, Vujicić G, Degenhardt C, Cervar M, Krempien B. Effects of parathyroidectomy on tissue calcium, phosphorus, magnesium, and copper concentrations in aluminum-loaded uremic rats. Biol Trace Elem Res 1989; 22:45-53. [PMID: 2484227 DOI: 10.1007/bf02917415] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Rats were subjected to a two-stage 5/6 nephrectomy and treated with Al for 2 and 4 wk with a cumulative dose of 4.2 and 8.4 mg of Al, respectively. Other animals were parathyrectomized (PTx) and loaded with 8.4 mg of Al for 4 wk. Total Al, Ca, P, Mg, and Cu contents were analyzed in the liver, kidney, and bone by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that Al given to growing uremic rats significantly increased the content of Al in the liver, kidney, and bone. Moreover, Al treatment increased the liver and kidney Ca levels and decreased the Ca and P values in bone. Previous parathyroidectomy significantly reduced Al accumulation within organs and changes in the Ca and P levels in the bone, liver, and kidney. The result was not influenced by different degrees of renal failure.
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Affiliation(s)
- S Vukicević
- Department of Anatomy, Zagreb University School of Medicine, Yugoslavia
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Vukicević S, Stavljenić A, Boll T, Cervar M, Degenhardt C, Mihaljević T, Krempien B. The influence of early parathyroidectomy on aluminum-induced rickets in growing uremic rats. Bone Miner 1989; 6:125-39. [PMID: 2765704 DOI: 10.1016/0169-6009(89)90045-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Rats were subjected to a two-stage 5/6 nephrectomy and treated with aluminum for 2 and 4 weeks with a cumulative dose of 4.2 and 8.4 mg of aluminum, respectively. Other animals were parathyroidectomized and loaded with 8.4 mg of aluminum for 4 weeks. Histomorphometry and electron microscopy (tibiae), aluminum tissue (bone, kidney, liver) determination, serum (Ca, Mg, Zn, P, urea, creatinine, alkaline phosphatase, 1,25(OH)2D3, PTH) and urine (creatinine, A1) revealed that: (a) a dose of 8.4 mg aluminum was sufficient to induce rickets within 4 weeks of treatment and was associated with decreased serum calcitriol values and high aluminum accumulation within organs (electron-dense material was found in osteoblasts only); (b) previous parathyroidectomy prevented the occurrence of any aluminum-induced alteration of bone. It was associated with higher calcitriol and phosphorus values than in corresponding non-parathyroidectomized rats and significantly reduced aluminum accumulation within organs. The results was influenced neither by a drop in serum calcium values nor by different degrees of renal failure. We suggest that aluminum-induced rickets in growing uremic rats is prevented or delayed when previous parathyroidectomy has been performed.
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Affiliation(s)
- S Vukicević
- Department of Anatomy, Zagreb University School of Medicine, Yugoslavia
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Abstract
Test-retest performance on the Wechsler Adult Intelligence Scale (WAIS) of two groups of adult epilepsy patients are presented and compared. In one group, Seizures Improved (SI) group, seizure frequency had decreased during the test-retest interval, and in the other group, Seizures Unimproved (SU) group, the number of seizures had either increased or stayed the same over the test-retest interval. The SI group showed a significant test-retest improvement on WAIS Verbal IQ, Performance IQ, and Full Scale IQ, as well as on eight of 11 WAIS subtests. In comparison, the SU group showed significant increases only on the Performance IQ and Object Assembly subtest. Furthermore, differences between the two groups were observed in the pattern of test-retest changes seen on the Performance measures relative to the Verbal measures. The results suggest that change in seizure frequency is one of the factors associated with test-retest changes in the intellectual functioning of epilepsy patients.
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