Article
Materials Science, Ceramics
Hyerin Jeong, Samuel Kimani Kihoi, Joseph Ngugi Kahiu, Hyunji Kim, Juhee Ryu, Kyu Hyoung Lee, Seonghoon Yi, Ho Seong Lee
Summary: The Nb1-xTixFe1.02Sb half-Heusler thermoelectric materials were synthesized by arc melting and subsequent spark plasma sintering (SPS). Doping Ti at Nb-site results in high power factor and reduced lattice thermal conductivity. Phonon scattering was enhanced at alternating interphase boundaries, leading to improved thermoelectric performance with a peak ZT of -0.81 at 973 K.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Chemistry, Physical
Ye Su, Yuan-Yuan Chen, Hao Wang, Hai-Kuan Dong, Shuo Cao, Li-Bin Shi, Ping Qian
Summary: Lead-free halide double perovskites of Cs2BiAgBr6 and Cs2BiAgCl6 have attracted extensive attention due to their potential applications in the optoelectronic field. In this study, we used machine learning interatomic potential (MLIP) to explore their lattice thermal conductivity and used semi-empirical models to predict their mobilities. It was found that the thermal conductivity was mainly controlled by low-frequency phonons, while the mobility was limited by the stretching between Bi and Br/Cl atoms.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Physics, Condensed Matter
E. Bolen, E. Deligoz, H. Ozisik
Summary: The mechanical, dynamical, and thermodynamic properties of monolayer PbI2 were studied comprehensively, showing its stability in both mechanical and dynamical aspects, but low thermal conductivity due to various factors.
SOLID STATE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
A. Magni, L. Luzzi, D. Pizzocri, A. Schubert, P. Van Uffelen, A. Del Nevo
Summary: This work presents original correlations for the thermal conductivity and melting temperature of minor actinide-MOX fuels, derived based on existing literature and accessible data. The statistical evaluation of these correlations shows their significance with respect to the experimental dataset used for fitting. The accuracy of these new correlations is in line with existing ones and state-of-the-art experimental uncertainties.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Chemistry, Inorganic & Nuclear
Hao Chen, Yingqin Wang, Jiaqing Su, Liyun Yang, Hao Bai
Summary: In this study, a molten salt method was proposed to prepare La2Zr2O7 by improving the kinetic conditions of synthesis. Different particle sizes of ZrO2 and La2O3 were used as raw materials, and the synthesis experiment was conducted at 900-1300 degrees C. The results showed that the particle size of ZrO2 played a crucial role in the synthesis of La2Zr2O7. The use of ZrO2 with a nominal particle size of 50 nm significantly improved the kinetic condition of the reaction, reducing the synthesis temperature and enabling energy-saving synthesis of pyrochlore La2Zr2O7.
INORGANIC CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Andrew J. Wright, Qingyang Wang, Yi-Ting Yeh, Dawei Zhang, Michelle Everett, Joerg Neuefeind, Renkun Chen, Jian Luo
Summary: Rare-earth niobates and tantalates possess low thermal conductivities, which can be further reduced in high-entropy compositions. The correlation between thermal conductivity and averaged radius ratio of cations is investigated, and short-range weberite-type order is found to be related to the reduced thermal conductivity. Diffuse scattering in X-ray diffraction and neutron total scattering confirms the presence of this order.
Article
Nanoscience & Nanotechnology
Sandip Thakur, Ashutosh Giri
Summary: Metal halide perovskites have attracted significant attention due to their remarkable structure-property relationships. Contrary to conventional belief, our atomistic simulations show that the enhancement in thermal conductivity is not due to guest ions' rattling behavior in the framework. Instead, the ultralow thermal conductivities primarily originate from the anharmonic and mechanically soft metal halide framework. Manipulating framework anharmonicity through strain and octahedral tilting is an efficient strategy to control heat transfer efficacy.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Fergany Badry, Monika Singh, Luis H. Ortega, Sean M. Mcdeavitt, Karim Ahmed
Summary: An experimentally validated mesoscale model was developed for metallic U and U-Zr fuels to simulate effective thermal conductivity. The effects of microstructure, temperature, composition, and interfacial thermal resistance were investigated, and companion experiments were conducted for model validation. The numerical simulations revealed the importance of considering interface thermal resistance and Zr precipitation in improving the model predictions. The largest difference between the model calculations and experimental data was about 4.5%, within the precision of the experimental measurements.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Ceramics
Dong Zhao, Andre Broussard, Tiankai Yao, Kevin Yan, Heng Ban, Jie Lian
Summary: This paper presents an innovative approach using spark plasma sintering (SPS) combined with finite element modeling (FEM) to study the transient behavior of nuclear fuels. The temperature ramping rates of SPS can simulate the thermal profiles of loss-of-coolant-accident (LOCA) and reactivity-induced-accident (RIA) events. Experimental results show that micron-sized fresh UO2 pellets synthesized by SPS exhibit good thermal shock stability and anti-cracking performance under LOCA thermal testing, while cracking occurs under simulated RIA conditions due to the stress induced by large thermal gradients. The unique capability of SPS with controlled temperature ramping enables a cost-effective method for rapid screening and evaluation of nuclear fuels under power transients.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2024)
Article
Chemistry, Physical
Lei Xu, Lifeng Zhang, Yubing Hu, Langli Luo
Summary: Two types of grain boundaries, macro and micro, were identified in LLTO pellets, with a nanosized Li-poor orthogonal phase found at micro-GBs negatively impacting Li conduction. The phase transformation process from tetragonal to orthogonal phase was revealed to be responsible for the deterioration in Li-ion conductivity, as La atoms moving to the Li-rich layer block the diffusion path of Li-ions in LLTO.
Article
Materials Science, Multidisciplinary
T. Pandey, Mao-Hua Du, David S. Parker, L. Lindsay
Summary: Inorganic lead-free halide double perovskites exhibit non-toxic and stable optoelectronic properties, as well as large thermoelectric potentials and high carrier mobilities, making them promising for thermoelectric applications.
MATERIALS TODAY PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Wilarachchige D. C. B. Gunatilleke, Winnie Wong-Ng, Peter Y. Zavalij, Mingjian Zhang, Yu-Sheng Chen, George S. Nolas
Summary: In this study, we investigate the structure and electrical transport of the single-crystal Eu2Ga11Sn35, which is a unique clathrate-I material with a very low cation concentration (25%) and shows atypical transport properties directly related to its structure and stoichiometry.
Article
Materials Science, Multidisciplinary
Kun Yang, Erofili Kardoulaki, Dong Zhao, Bowen Gong, Andre Broussard, Kathryn Metzger, Joshua T. White, Michael R. Sivack, Kenneth J. Mcclellan, Edward J. Lahoda, Jie Lian
Summary: Spark plasma sintering was used to fabricate Cr-incorporated UN composite fuels, and it was found that the addition of Cr improved the thermal conductivity, hardness, fracture toughness, and oxidation resistance of the fuels. The formation of a Cr enriched phase enhanced the liquid sintering characteristic. These findings are significant for enhancing the thermal-mechanical properties of UN fuels with well-maintained high fissile element density.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Floyd W. Hilty, Dong-Uk Kim, Michael R. Tonks
Summary: This study investigates the impact of fission gas bubbles on the effective thermal conductivity (ETC) of composite nuclear fuels. The results show that fission gas bubbles may completely eliminate the benefits of high thermal conductivity additives, leading to even lower thermal conductivity than fuel without additives. A trend relating the fraction of additive screened by bubbles to the ETC is identified, and a model is proposed to predict the ETC of composite fuels with fission gas bubbles for better estimation of fuel design benefits.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Thermodynamics
Haider Ali, Hussain Al-Qahtani, Bekir Sami Yilbas, Saad Bin Mansoor
Summary: The study focused on the thermal conductivity of low-dimensional structures composed of silicon-aluminum films and the importance of assessing thermal resistance contributions for stable operation. By incorporating various thermal resistances, the effective thermal conductivity was evaluated, showing agreement with early formulations for the silicon film. Increasing the thickness of the silicon film in the structure was found to enhance the thermal conductivity.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
