Article
Materials Science, Multidisciplinary
Yao Zhang, Jinlin Li, Hongyao Yu, Jiudong Sun, Zhenhua Wang, Qing Wang
Summary: The present study investigated the effect of Ti, Nb, or Ta addition on the microstructural stability of coherent gamma/gamma ' phases in designed high-temperature alloys. The results showed that the addition of Ti, Nb, or Ta not only reduced the size of gamma ' nanoparticles, but also improved the microstructural stability during aging, leading to enhanced mechanical properties.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Chemistry, Physical
Hao Zhu, Chenchen Zhao, Pengfei Nan, Xiao-ming Jiang, Jiyin Zhao, Binghui Ge, Chong Xiao, Yi Xie
Summary: Understanding the intrinsic lattice thermal conductivity in (Bi-2)(m)(Bi2Te3)(n) compounds involves the interaction between heat-carrying acoustic phonons and low-frequency optical phonons, chemical bond softening, lattice anharmonicity, and small Brillouin zone volume contributing to low cutoff frequency of acoustic phonon modes. These mechanisms together result in intrinsically low lattice thermal conductivity, making the compounds potential candidates for future thermoelectric applications and guiding the design of materials with desired thermal transport properties.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Physical
Sonya Harizanova, Eric Faulques, Benoit Corraze, Christophe Payen, Marcin Zajac, Dorota Wilgocka-Slezak, Jozef Korecki, Genoveva Atanasova, Radostina Stoyanova
Summary: By forming multiphase composites with distinct electrical and thermal conductivities, the thermoelectric activity of oxides can be modified. The interfacial chemical and electrical properties of the composites play a crucial role in determining the thermoelectric performance, with the highest activity observed in composites richer in perovskite.
Article
Materials Science, Multidisciplinary
Dong-Ming Jin, Zhen-Hua Wang, Jin-Feng Li, Ben Niu, Qing Wang
Summary: This study investigated the formation and strengthening mechanism of coherent BCC/B2 microstructure in Al-Ti-Zr-Nb-Ta-Cr/Mo refractory high-entropy alloy system. It found that the alloy with Cr0.5Mo0.5 exhibited the best mechanical performance after aging at 873 K.
Article
Materials Science, Multidisciplinary
Jin Hee Kim, Jae Hyun Yun, Yoo Jang Song, Jong-Soo Rhyee
Summary: The (SnSe)(1.17)(TaSe2) compound exhibits both thermoelectric and superconducting properties, with anisotropic characteristics observed from XRD and electrical resistivity measurements. Results from density functional theory (DFT) calculations indicate electronic charge transfer, while the compound's thermoelectric properties also show significant anisotropy.
CURRENT APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Hye Ji Im, Surendra K. Makineni, Chang-Seok Oh, Baptiste Gault, Pyuck-Pa Choi
Summary: This study investigated the use of atom probe tomography in Co-12Ti-4Mo-Cr alloys with gamma/gamma' phases. The addition of moderate amounts of Cr reduced lattice misfit and increased the volume fraction of gamma', leading to changes in elemental partitioning and site-occupancy within the phases. Thermodynamic calculations supported the experimental data by predicting the preferential occupation of Mo in Co-sites and an increase in Cr fraction in Ti-sites with higher Cr content.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Kateryna Smyrnova, Martin Sahul, Marian Harsani, Alexander Pogrebnjak, Volodymyr Ivashchenko, Vyacheslav Beresnev, Vyacheslav Stolbovoy, Lubomir Caplovic, Maria Caplovicova, Lubomir Vanco, Martin Kusy, Alexey Kassymbaev, Leonid Satrapinskyy, Dominik Flock
Summary: This work investigates the microstructure, phase composition, mechanical and tribological properties of WN-based nanocomposite multilayers with a second MeN (Me = Zr, Cr, Mo, Nb) layer. WN/MoN multilayers were studied for the first time using cathodic-arc physical vapor deposition (CA-PVD). First-principles calculations were also performed to gain more insight into the properties of the deposited multilayers. Among the four studied systems, WN/NbN showed the best performance as a protective coating in challenging conditions.
Article
Nanoscience & Nanotechnology
Brandon Ohl, David C. Dunand
Summary: The effects of Ni and Cr additions on microstructure, lattice misfit, oxidation, and creep properties in cobalt-based superalloys were studied. It was found that changes in the Ni and Cr content have an impact on the materials' performance.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Engineering, Environmental
Mingzhe Leng, Jianqiang Bi, Zheng Xing, Weili Wang, Xicheng Gao, Jingyu Wang, Zhao Qian
Summary: The study investigates a new family of layered transition metal oxides in sodium-ion batteries, demonstrating high specific capacity, superior rate performance, and high coulombic efficiency. In-depth understanding of the material's intrinsic structure and electrochemical performance could potentially offer new insights for material design and development.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
Rahul Mitra, Taraknath Maity, Nidhi Sharma, Khushubo Tiwari, Tanmoy Maiti, Krishanu Biswas
Summary: The gradual evolution of equimolar (Nb, Ti, Zr, Cr)B-2 was studied through boro-carbothermal reduction of metal oxides with varying B4C content. The phase evolution and microstructural investigation revealed the formation of a high-entropy boride (HEB) phase with a small amount of retained phases for a certain B4C content. The sintered specimens exhibited high hardness and thermal conductivity, making this methodology a promising route for obtaining multicomponent diborides.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Engineering, Manufacturing
A. D. Iams, T. J. Lienert, D. A. Otazu, M. Ramoni
Summary: Although Cu-Cr-Nb alloys / superalloys bimetallic components for liquid rocket engine applications have been fabricated using additive manufacturing, a detailed understanding of their process-structure relation is currently lacking. To bridge this gap, GRCop-42 / Alloy 718 bimetallic structures were fabricated with two different deposition sequences, revealing significant variations in precipitate morphology, composition, and crystal structure within the GRCop-42 material depending on the deposition sequence.
ADDITIVE MANUFACTURING LETTERS
(2023)
Article
Physics, Applied
Raju Chetty, Priyanka Jood, Masayuki Murata, Koichiro Suekuni, Michihiro Ohta
Summary: This study demonstrates the thermoelectric power generation capability of a prototype pi-shaped module composed of p-type colusite and n-type nanostructured PbTe, and evaluates the thermoelectric performance of the materials. The optimal working temperature and thermoelectric conversion efficiency for Cu26Cr2Ge6S32 and Pb0.98Ga0.02Te-3% GeTe are determined.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Keita Toh, Koichiro Suekuni, Katsuaki Hashikuni, Hirotaka Nishiate, Ushin Anazawa, Chul-Ho Lee, Michitaka Ohtaki
Summary: It has been shown that ball milling and sintering processes can effectively reduce the secondary phases in alpha-MgAgSb samples, contributing to improved sample purity and thermoelectric performance. Further reduction of secondary phases and enhancement of ZT values can be achieved by decreasing the starting Ag content.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Chemistry, Inorganic & Nuclear
Shota Hirayama, Koichiro Suekuni, Philipp Sauerschnig, Michihiro Ohta, Michitaka Ohtaki
Summary: In this study, the thermoelectric properties of Cu-S-based semiconducting compound and its hole-doped derivatives were synthesized and tested. Hole-carrier doping effectively reduced electrical resistivity and improved power factor. The Ti-doped compound showed better thermoelectric performance due to its low lattice thermal conductivity and improved power factor.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Materials Science, Ceramics
Nhat Quang Minh Tran, Michitaka Ohtaki, Koichiro Suekuni
Summary: High-temperature thermoelectric properties of tungsten-based Magne'li phase oxide (W1-xTix)18O49 (0 < x < 0.25) prepared by solid state reaction followed by densification via spark plasma sintering (SPS) were studied. The Ti substitution increased the Seebeck coefficient, the power factor, and decreased both the electronic and lattice thermal conductivity, leading to a significantly high ZT of 0.50 +/- 0.07 at 1073 K for the sample with x = 0.2.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
V. Pavan Kumar, S. Passuti, B. Zhang, S. Fujii, K. Yoshizawa, P. Boullay, S. Le Tonquesse, C. Prestipino, B. Raveau, P. Lemoine, A. Paecklar, N. Barrier, X. Zhou, M. Yoshiya, K. Suekuni, E. Guilmeau
Summary: Understanding the mechanisms connecting heat, electron transport, crystal structures, and defect chemistry is crucial for developing materials with thermoelectric properties. In this study, we synthesized self-doped compounds Cu2+xMn1-xGeS4 and used advanced characterization techniques to reveal the presence of interconnected nanodomains with high-density coherent interfaces. By combining experiments with ab initio calculations, we discuss the relationship between the crystal structure and thermoelectric properties, and demonstrate that substituting excess Cu+ for Mn2+ significantly enhances the power factor and figure of merit ZT.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Meiqi Zhang, Fabien Grasset, Yuji Masubuchi, Toshihiro Shimada, Thi Kim Ngan Nguyen, Noee Dumait, Adele Renaud, Stephane Cordier, David Berthebaud, Jean-Francois Halet, Tetsuo Uchikoshi
Summary: The Mo cluster-MoS2 composite was synthesized through a one-step sulfurization process using H2/H2S gas flow. The decomposed Mo-6 cluster iodides acted as a template and precursor, forming complex Mo cluster compounds and eventually producing MoS2. After sulfurization, the response of the composite to NH3 gas increased three times while showing conversion from p-type to n-type semiconductor, enhancing its potential for device applications.
Review
Chemistry, Multidisciplinary
Philipp Sauerschnig, Priyanka Jood, Michihiro Ohta
Summary: For decades, efforts have been made to improve the thermoelectric figure of merit zT of lead telluride (PbTe)-based materials. However, their applications have been limited to space probes and remote locations. One of the obstacles in implementing thermoelectrics is establishing stable electrical and thermal contacts between PbTe-based materials and electrodes. This review summarizes the challenges and recent progress in bonding PbTe and contact layer, focusing on contact resistance, chemical stability, and mechanical stability.
Article
Materials Science, Multidisciplinary
Philipp Sauerschnig, Priyanka Jood, Michihiro Ohta
Summary: By adjusting the Na doping content, the material stability and mechanical properties of nanostructured p-type Pb0.993-xNaxGe0.007Te are improved while maintaining a high thermoelectric figure of merit zT. The presence of detrimental Na-rich impurity phases is eliminated by reducing the Na doping from 4% to 2%. Co80Fe20 contact layers improve the conversion efficiency of Pb0.973Na0.02Ge0.007Te and Pb0.98Ga0.02Te.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Thermodynamics
Minhyeok Lee, Gyeonghun Yoo, Junjie Peng, Shintaro Uchida, Atsushi Yamamoto, Yuji Suzuki
Summary: A novel micro thermoelectric power generation module has been proposed, which directly heats the hot junction of high-temperature plate-type TEG elements through localized catalytic combustion. The convection effect with unburned mixture flows is utilized to recover heat losses caused by heat conduction. The study shows that with the aid of the convection effect, temperature differences over 700 degrees C can be achieved between the hot/cold junctions while maintaining a low unreacted fuel concentration.
APPLIED THERMAL ENGINEERING
(2023)
Article
Chemistry, Physical
Takashi Hagiwara, Koichiro Suekuni, Pierric Lemoine, Carmelo Prestipino, Erik Elkaim, Andrew R. Supka, Rabih Al Rahal Al Orabi, Marco Fornari, Emmanuel Guilmeau, Bernard Raveau, Hikaru Saito, Philipp Sauerschnig, Michihiro Ohta, Yui Kanemori, Michitaka Ohtaki
Summary: Copper-based sulfide Cu(3)0Ti(6)Sb(2)S(32) with a colusite-like cubic structure is synthesized and characterized in this study. The electronic structure and vibrational properties are investigated using experiments and first-principles calculations. The design approach based on the pseudobinary composition is demonstrated to be a promising direction for the discovery of new copper-based sulfides with tunable transport properties.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Sylvain Le Tonquesse, Hugo Bouteiller, Yoshitaka Matsushita, Araseli Cortez, Sabah K. Bux, Kazuki Imasato, Michihiro Ohta, Jean-Francois Halet, Takao Mori, Franck Gascoin, David Berthebaud
Summary: This article introduces a high-temperature thermoelectric material Yb4Sb3 and its application in the fabrication of high-temperature thermoelectric modules. It is found that the doping strategy can improve the figure-of-merit of the thermoelectric material through the study of doubly doped CexYb4-xBi0.2Sb2.8 compounds. Furthermore, the study of metallic contact screening for the thermoelectric module successfully produced stable contacts for the thermoelectric legs.
ACS APPLIED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Kazuki Imasato, Philipp Sauerschnig, Shashwat Anand, Takao Ishida, Atsushi Yamamoto, Michihiro Ohta
Summary: In this study, triple half-Heusler compound Mg2VNi3Sb3 with unconventional valence balance strategy was successfully synthesized. It exhibits semiconductor behavior with a small bandgap and low lattice thermal conductivity. This research demonstrates a new strategy for further improvement of thermoelectric performance and extended tunability of intermetallic compounds.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)