Article
Materials Science, Ceramics
Sree Koundinya Sistla, Tarini Prasad Mishra, Yuanbin Deng, Anke Kaletsch, Martin Bram, Christoph Broeckmann
Summary: This study investigated the effect of the electrical field on microstructure evolution during field-assisted sintering of gadolinium-doped ceria. Enhanced grain growth was observed near the anode under certain conditions. Both experimental and numerical methods were used to analyze grain growth kinetics and the results were in agreement.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Tarini Prasad Mishra, Christian Lenser, Rishi Raj, Olivier Guillon, Martin Bram
Summary: Flash sintering is a rapid sintering method suitable for oxides and complex ceramics. Electrical parameters, such as electric field and electric current, influence the onset temperature and densification of flash sintering. Developing a processing map, exemplified by gadolinium-doped ceria, can guide flash sintering in different material systems.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Vaclav Tyrpekl, Marco Cologna, Michael Holzhauser, Petr Svora
Summary: This paper investigates the process of flash spark plasma sintering (FSPS) and the densification process of Gd0.1Ce0.9O2-x powder, finding that low electrical fields are sufficient for flash sintering to occur. The study discusses the challenges of sintering ceria using FAST techniques due to its mechanochemical transformations.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Ji-Hwoan Lee, Byung-Nam Kim, Ji-Guang Li, Byung-Koog Jang
Summary: Transparent Ce3+:(Gd,Lu)3Al5O12 material with microstructure control was fabricated using two-step spark plasma sintering. The two-step profile resulted in smaller grain size and lower porosity compared to the single-step profile, leading to increased transmittance.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Mario Godinho, Murillo H. M. Rodrigues, Rosana de F. Goncalves, Roman Alvarez Roca, Elson Longo, Fabiana Villela Mota, Humberto V. Fajardo, Rosana Balzer
Summary: This study investigates the relationship between ionic conductivity and catalytic activity of ionic conductors based on gadolinium-doped ceria (GDC). Experimental results show that samples with 15% gadolinium exhibit higher catalytic activity and ionic conductivity at 400 degrees C. The study attempts to correlate conductivity and catalytic oxidation in terms of oxygen mobility, vacancies, and superoxide formation.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Bharathi Bandi, Abhijit Chatterjee
Summary: The ionic conductivity of polycrystalline aliovalently-doped solid oxide electrolytes is lower than that of single-crystal material due to slow ionic movement at the grain boundary. Traditional models fail to consider the chemical interactions and atomic structure at the grain boundary. Molecular dynamics simulations reveal chemical oscillation in the space-charge region, resulting from competing chemical, electrostatic, and elastic interactions. The characteristics of the space charge layer differ in each grain boundary, and an alternative theory explaining these chemical oscillations is proposed.
Article
Materials Science, Ceramics
Adam Alemayehu, Mattia Biesuz, Kimia Y. Javan, Alexander Tkach, Paula M. Vilarinho, Vincenzo M. Sglavo, Vaclav Tyrpekl
Summary: Ultrafast high-temperature sintering (UHS) is a rapidly growing research area in material science and engineering. In this study, single and multi-step approaches were used to UHS gadolinia-doped ceria (GDC) powders. The sintered ceramics were characterized both physically and electrochemically. With a gradual application of power during the multistep UHS process, crack-free GDC ceramics with 95% bulk density can be obtained using commercial powder. The same multistep sintering process using oxalate converted GDC powder resulted in 86% bulk density. It was also demonstrated that multistep UHS is suitable for multilayer cosintering necessary for solid oxide fuel cells (SOFC), as evidenced by the production of dense GDC electrolyte in tight contact with porous electrodes.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Ceramics
Yuye Zhao, Jian Tang, Hongliang Xu, Lei Zhu, Na Ni
Summary: This study introduces a reactive cold sintering method which uses precursors to increase the density of gadolinia-doped ceria (GDC) ceramics at lower annealing temperatures. By adding stoichiometrically mixed precursors during the cold sintering process, the relative density of the GDC compacts was significantly improved. The study also investigated the sintering mechanism and found that the precursor reaction effectively filled the gaps between the particles, promoting densification of the samples.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Chemistry, Physical
Leticia P. R. Moraes, Marina Machado, Lays N. Rodrigues, Ziqi Sun, Debora Marani, Fabio C. Fonseca
Summary: A novel method for synthesizing two-dimensional gadolinium-doped cerium oxide nanosheets as interdiffusion barrier layers in solid oxide fuel cells is developed. The shape of the nanosheets is controlled using a low-cost wet-chemical method, allowing for the fabrication of a dense barrier layer. The electrochemical properties of the fuel cells confirm the efficiency of the cerium oxide nanosheets in preventing the formation of resistive phases at the interface.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Ceramics
Ashok Kumar Baral, Yoed Tsur
Summary: Many metal oxides exhibit thermo-chemical expansion that can lead to mechanical failure in devices such as solid oxide fuel cells. This study demonstrates the separation of expansion caused by chemical effects from pure thermal effects using temperature modulated dilatometry. However, different chemical effects at different temperatures complicate the analysis.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Chemistry, Physical
X. Y. Ping, B. Meng, W. K. Liang, Q. Zheng, C. Li
Summary: In this study, composite powders of Ce0.85Y0.15O2-delta (YDC)-xmol% aluminum compound were prepared by mixing YDC with different amounts of Al(NO3)(3) and densified through spark plasma sintering. The formation of CeAlO3 phase and reduction in grain size were observed with increasing Al(NO3)(3) addition amount. While the presence of CeAlO3 phase in A10 and A20 samples decreased the grain boundary conductivity, the evenly distributed CeAlO3 grains in A40 led to a significant increase in grain boundary conductivity.
SOLID STATE IONICS
(2021)
Article
Nuclear Science & Technology
Wenxian Wang, Jie Zhang, Shipeng Wan, Tingting Zhang
Summary: The constitutive equation of the Gd-155/157 areal density and thermal neutron shielding rate was established to design novel Gd/316L stainless steel thermal neutron shielding materials, which showed a high absorption rate when the Gd-155/157 areal density is above 0.01 g/cm(2). Different Gd contents were prepared using spark plasma sintering, forming a transition layer during the process and impacting the mechanical properties of the composites. Pitting and galvanic corrosion were observed at the interface between Gd and 316L matrix in a H3BO3 solution.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Materials Science, Multidisciplinary
Akihiro Ishii, Hibiki Ishijima, Kosei Kobayashi, Itaru Oikawa, Hitoshi Takamura
Summary: The key element for low-temperature sintering of Sm-doped CeO2 was found to be aluminum, which was spontaneously introduced through a chemical reaction with mixed lithium and alumina crucible. Zirconium was also introduced through ball-mill processing. Both aluminum and zirconium play an important role in reducing the melting point and achieving low-temperature sintering.
Article
Chemistry, Multidisciplinary
Yongwei Chen, Sol Ahn, Mohammad Rasel Mian, Xingjie Wang, Qing Ma, Florencia A. Son, Lifeng Yang, Kaikai Ma, Xuan Zhang, Justin M. Notestein, Omar K. Farha
Summary: Solid supports play a crucial role in heterogeneous catalysis, but their specific effects remain challenging to elucidate. In this study, metal-organic frameworks (MOFs) with 8-connected Zr-6 nodes were used as supports to deposit molybdenum(VI) and investigate the effects of pore environment and topology on the resulting catalysts. It was found that by modulating the chemical environments of the deposited molybdenum species, the catalytic activity and structure can be changed. This work demonstrates the importance of using MOF supports to construct heterogeneous catalysts and elucidate structure-activity relationships in reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Materials Science, Ceramics
Igor V. Zagaynov, Ivan V. Shelepin, Sergey V. Fedorov, Alexander V. Naumkin, Alexey V. Bykov, Anatoly A. Konovalov
Summary: Ceria based solid solution doped with copper, manganese, and rare earth elements were synthesized and shown to have enhanced surface area and oxygen mobility. The catalytic activity in CO oxidation was higher in samples containing neodymium compared to samarium. These materials also showed potential as solid electrolytes for intermediate temperature solid oxide fuel cells.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Multidisciplinary
Christoph Vorkoetter, Daniel Emil Mack, Robert Vassen, Olivier Guillon
Summary: This study introduces a new laser-cladding-based additive manufacturing technique called Clad2Z, which utilizes a robot-mounted confocal powder nozzle and axial infrared laser beam to develop ceramic columns. The influence of laser parameters and robot movements on shape and microstructure is analyzed, and the excellent thermal cycling performance of Clad2Z samples in terms of thermal barrier coatings is demonstrated through burner rig tests and comparison with conventional TBC systems.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Review
Chemistry, Physical
Stephan Sarner, Andrea Schreiber, Norbert H. Menzler, Olivier Guillon
Summary: This paper discusses potential recycling routes for solid oxide fuel cell (SOC) stack components, with emphasis on ceramic fractions. The economic and environmental potentials of recycling are evaluated, demonstrating significant advantages offered by recycling.
ADVANCED ENERGY MATERIALS
(2022)
Article
Metallurgy & Metallurgical Engineering
Siyuan Qin, Simone Herzog, Anke Kaletsch, Christoph Broeckmann
Summary: Laser additive manufacturing allows for the efficient production of complex parts, but the presence of pores and carbide networks in the laser powder-bed fusion (LPBF) process can reduce fatigue strength. Hot isostatic pressing (HIP) with integrated heat treatment effectively densifies the material and alters its microstructure, leading to improved fatigue strength. Research findings demonstrate that the HIP process significantly enhances the fatigue strength of the samples.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Energy & Fuels
Moritz L. Weber, Moritz Kindelmann, Egbert Wessel, Alexandros Sarantopoulos, Norbert H. Menzler, Regina Dittmann, Rainer Waser, Olivier Guillon, Christian Lenser, Felix Gunkel
Summary: Metal exsolution is a dynamic process driven by reducing atmosphere and elevated temperatures, which leads to the self-assembly of nanoparticles at the surface of complex perovskite catalysts. The characteristics of metal exsolution catalysts can be highly inhomogeneous, and the anisotropic surface properties of ceramic oxides have been found to significantly affect the exsolution behavior.
JOURNAL OF PHYSICS-ENERGY
(2023)
Article
Nanoscience & Nanotechnology
Martin Ihrig, Liang-Yin Kuo, Sandra Lobe, Alexander M. Laptev, Che-an Lin, Chia-hao Tu, Ruijie Ye, Payam Kaghazchi, Luca Cressa, Santhana Eswara, Shih-kang Lin, Olivier Guillon, Dina Fattakhova-Rohlfing, Martin Finsterbusch
Summary: All-solid-state lithium batteries are promising for energy storage, but suffer from performance degradation during cycling. This study shows that thermal recovery can recrystallize the amorphized interface, restoring the cell performance. Detailed analysis and thermodynamic modeling provide a comprehensive understanding of the structural and chemical changes. Through thermal recovery, more than 80% of the initial storage capacity can be recovered, offering potential for cost-efficient recycling of ceramic all-solid-state batteries.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Ceramics
Maria Wisniewska, Alexander M. Laptev, Mateusz Marczewski, Volf Leshchynsky, Grzegorz Lota, Ilona Acznik, Luca Celotti, Alex Sullivan, Miroslaw Szybowicz, Dariusz Garbiec
Summary: Carbon nanotubes (CNTs) are widely used in ceramic-matrix composites (CMC) as a filler. They have high thermal conductivity individually, but only have a moderate influence on the thermal conductivity of CMCs. However, even a small quantity of CNTs can significantly increase the electrical conductivity of CMCs. The present study investigates the influence of multi-wall carbon nanotubes (MWCNTs) on the thermal and electrical conductivity of ZrO2-CNTs composites, revealing the contradictory effects of CNTs on these properties.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Multidisciplinary
Andrea Schreiber, Melanie Rosen, Katja Waetzig, Kristian Nikolowski, Nikolas Schiffmann, Hartmut Wiggers, Michael Kuepers, Dina Fattakhova-Rohlfing, Wilhelm Kuckshinrichs, Olivier Guillon, Martin Finsterbusch
Summary: All-solid-state batteries are a promising research topic for their high energy density and safety. However, implementing oxide ceramic electrolytes in industrial cells remains challenging. To address this, researchers proposed a target cell design combining two promising oxidic electrolytes, LLZO and LATP, and assessed their environmental impact. In-depth life cycle assessment revealed surprising similarities between oxide-based all-solid-state batteries and conventional Li-ion batteries.
Article
Metallurgy & Metallurgical Engineering
Gezhou Wang, Yuanbin Deng, Frank Adjei-Kyeremeh, Jiali Zhang, Iris Raffeis, Andreas Buehrig-Polaczek, Anke Kaletsch, Christoph Broeckmann
Summary: In this study, various computational fluid dynamics models were used to simulate the gas atomisation process. The results show that a reasonable mass median diameter of the particle can be predicted numerically, and there is a clear relationship between the breakup trajectory and the resulting particle size.
Article
Chemistry, Physical
Fabian Meyer, Fabian Kolodzy, Marie Luise Scheck, Anke Kaletsch, Tetiana Kharandiuk, Andrij Pich, Christoph Broeckmann
Summary: In order to expand the range of alloys that can be processed by laser-based powder bed fusion, reinforced alloys have been the focus of attention. The satelliting method, which uses a bonding agent to add fine additives to larger parent powder particles, was introduced to prevent local demixing caused by size and density effects. This study investigates the use of the satelliting method with a functional polymer binder (pectin) to add Cr3C2 to AISI H13 tool steel. The results suggest that pectin is a suitable binder for the satelliting process, reducing the demixing behavior observed in simple powder blends. However, the alloy becomes enriched with carbon, resulting in the retention of austenite. Further research will explore the use of a reduced binder content.
Article
Chemistry, Physical
Anke Kaletsch, Siyuan Qin, Christoph Broeckmann
Summary: This study investigates the influence of different build orientations and two different heat treatment conditions on the creep properties of additively manufactured Inconel 718 alloy. The results show that the build direction has a slight influence on the creep properties, while the heat treatment conditions have a more significant impact. The specimens subjected to hot isostatic pressing (HIP) treatment exhibit better creep resistance than those treated with solution annealing at 980 degrees C followed by aging.
Article
Chemistry, Physical
Anke Kaletsch, Markus Sondermann, Markus Mirz, Felix Radtke, Christoph Broeckmann
Summary: Laser-based additive manufacturing is a promising technology for producing parts with complex geometries. Hot isostatic pressing (HIP) is often used to enhance the strength and reliability of parts produced via powder bed fusion with laser beam (PBF-LB). This study investigates the influence of argon and nitrogen as process gases on the properties of duplex AISI 318LN steel after PBF-LB and HIP, focusing on high initial porosities.
Article
Materials Science, Ceramics
Chao Liu, Mathias Herrmann, Yuanbin Deng, Anke Kaletsch, Christoph Broeckmann
Summary: The uniaxial viscosity, which is affected by temperature, relative density, and grain size, plays a crucial role in understanding material densification during the sintering process. In this study, bending creep tests are conducted on pre-sintered 3Y-TZP specimens with varying relative densities and grain sizes to determine the uniaxial viscosity and its dependence on these factors. It is found that the uniaxial viscosity decreases with temperature, and the tetragonal to cubic phase transformation at high temperatures reduces the activation energy. The contributions of densification and grain growth to the increase in uniaxial viscosity are quantitatively determined.
CERAMICS INTERNATIONAL
(2023)
Article
Green & Sustainable Science & Technology
Monica Keszler, Felix Grosswendt, Anna-Caroline Assmann, Martin Krengel, Fernando Maccari, Oliver Gutfleisch, Doris Sebold, Olivier Guillon, Sebastian Weber, Martin Bram
Summary: Recycling of Nd-Fe-B magnets is a challenge, but combining FAST/SPS and flash SPS techniques can directly produce magnets from 100% scrap material with properties similar to commercial magnets.
ADVANCED ENERGY AND SUSTAINABILITY RESEARCH
(2023)
Article
Energy & Fuels
Vishnu Ganesh, Daniel Dorow-Gerspach, Martin Bram, Christian Linsmeier, Jiri Matejicek, Monika Vilemova
Summary: The realization of the first wall (FW) in future fusion reactors, which is composed of a tungsten (W) armor covering steel material, is a critical challenge. This study benchmarks two joining concepts to address the cyclic thermal stress issue caused by the different coefficients of thermal expansion (CTE) of W and steel. One concept uses an atmospheric plasma sprayed graded interlayer, while the other uses a spark plasma sintered graded interlayer. The results show that the joints with a plasma sprayed graded interlayer and a vanadium interlayer can withstand higher heat flux.
Article
Nuclear Science & Technology
D. Dorow-Gerspach, M. Bram, V. Ganesh, J. Matejicek, G. Pintsuk, M. Vilemova, M. Wirtz, C. Linsmeier
Summary: The joining of tungsten and steel is crucial for future commercial fusion reactors, but the large difference in their coefficient of thermal expansion can lead to high thermal stresses and premature failure of the joint. Two solutions explored in this study are the use of functionally graded materials with varying thermal expansion coefficients and the insertion of a ductile metal interlayer. Different joining technologies were evaluated through high heat flux benchmark tests.
NUCLEAR MATERIALS AND ENERGY
(2023)
