The effect of SPS processing parameters on the microstructure and thermal conductivity of ThO2

Malakkal, Linu; Prasad, Anil; Ranasinghe, Jayangani I.; Jossou, Ericmoore; Oladimeji, Dotun; Szpunar, Barbara; Bichler, Lukas; Szpunar, Jerzy A.

doi:10.1016/j.jnucmat.2019.151811

Cited by 8 publications

(2 citation statements)

References 27 publications

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“…The densities of ThO 2 ceramics obtained in this study are between that of the ceramic prepared using commercial powder (only 85% TD) and the spark plasma sintering process (95% TD). 55,56 Figure 7c shows the thermal conductivity of the ThO 2 ceramics derived from the experimental thermal diffusivity. Similar to thermal diffusivity, the thermal conductivity of the ceramics decreases with increasing temperature, and the difference between thermal conductivities tends to decrease.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Thorium Dioxide Nanocrystals via Molten Salt Thermal Decomposition for Nuclear Energy-Related Applications

Zhang

Qian

Liu

et al. 2022

ACS Appl. Nano Mater.

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In addition to uranium, thorium is a vital nuclear element that has broad potential for future nuclear energy applications. Herein, we report the synthesis of cubic structured ThO2 nanocrystals (NCs) based on the decomposition of their nitrate salt in air and in a molten salt medium. Both the processes yield pure ThO2 NCs with average sizes of <100 nm. The ThO2 NCs synthesized in the molten salt medium exhibit better crystallinity and a larger average size of ∼75.1 nm with a narrow size distribution owing to the high-temperature liquid growth environment. The ceramic sintered from the salt-derived ThO2 NCs exhibits a considerably higher relative density of 94.6% and similar thermal properties compared with the ceramic fabricated from fine nanopowders (<10 nm) obtained from direct thermolysis of metal nitrate. This study shows that thermal decomposition in a molten salt medium could be an efficient method for producing highly crystalline metal-oxide NCs of thorium-based fuels used in nuclear energy applications.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Thorium Dioxide Nanocrystals via Molten Salt Thermal Decomposition for Nuclear Energy-Related Applications

Zhang

Qian

Liu

et al. 2022

ACS Appl. Nano Mater.

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“…In recent years, nuclear fuel researchers have increasingly turned their attention to Spark plasma sintering (SPS), an innovative powder consolidation technique that affords shorter processing times at lower temperatures than traditional methods [3][4] [5]. Consequently, SPS of CeO2 holds great significance in nuclear fuel research, particularly in studies related to the fabrication of accident-tolerant fuels.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Densification of Cerium (IV) Oxide during Spark Plasma Sintering under a Carbon Dioxide Atmosphere

Prasad,

Malakkal,

Bichler

et al. 2024

Preprint

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Cerium dioxide (CeO2) finds extensive utility in electro ceramics applications, including solid oxide fuel cells, oxygen sensors, and catalysts. However, Spark Plasma Sintering (SPS) of CeO2 presents challenges due to the heightened mobility of O2− ions in the presence of an electric field, as well as its reactivity with graphite tooling. Traditionally, CeO2 is sintered in an oxidative environment to prevent it from reducing to CeO2−δ or Ce2O3. Nevertheless, oxidative atmospheres are detrimental to the graphite and steel tooling used in SPS processing. In this study, we investigated CeO2 SPS in a CO2 atmosphere and observed substantial enhancement in the relative density (RD) of the as-sintered samples in comparison to those sintered in an Ar atmosphere. The improved densification is attributed to reduced formation of oxygen vacancies in the CO2 atmosphere. Furthermore, the reaction between CeO2 and graphite generates COx gases, and that reaction can be reversed in a CO2 atmosphere. In summary, CeO2 SPS in a CO2 environment demonstrates superior densification, effectively mitigating the challenges associated with ionic mobility and graphite reactivity.

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Synthesis of Thorium Dioxide Nanocrystals by Pyrolysis of a Thorium‐based Metal‐organic Framework

Qian

et al. 2022

ChemistrySelect

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A new method is demonstrated for synthesizing thorium dioxide (ThO2) nanoparticles (NPs) by thermal decomposition of an undiscovered thorium‐based metal‐organic framework (MOF). Upon heating at 520 °C, the thorium‐based MOF crystals, designated Th‐MTB, are converted completely to ThO2 NPs with an average size of 150 nm. The MOF‐derived ThO2 NPs are easily sintered to form ThO2 ceramics which have good thermal conductivity. The crystalline grains of ThO2 grow continuously during sintering.The method for the synthesis of ThO2 NPs could have potential applications in the production of nuclear materials.

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The effect of SPS processing parameters on the microstructure and thermal conductivity of ThO2

Cited by 8 publications

References 27 publications

Synthesis of Thorium Dioxide Nanocrystals via Molten Salt Thermal Decomposition for Nuclear Energy-Related Applications

Synthesis of Thorium Dioxide Nanocrystals via Molten Salt Thermal Decomposition for Nuclear Energy-Related Applications

Enhanced Densification of Cerium (IV) Oxide during Spark Plasma Sintering under a Carbon Dioxide Atmosphere

Synthesis of Thorium Dioxide Nanocrystals by Pyrolysis of a Thorium‐based Metal‐organic Framework

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