A molecular dynamics survey of grain boundary energy in uranium dioxide and cerium dioxide

Zhang, Yongfeng; Hansen, Evan D; Harbison, Tim; Masengale, Sean; French, Jarin; Aagesen, Larry K.

doi:10.1111/jace.18340

Cited by 11 publications

(5 citation statements)

References 51 publications

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“…As explained earlier, the GB energy is the excess energy per unit area resulting from the disordered structure, relative to the energy of a perfect crystal. As one of the most fundamental material parameters, GB energy has a great impact on a variety of properties, including thermal conductivity, thermal resistance, fracture toughness, and fission gas release . For example, GBs often scatter phonons (vibration quanta that carry heat energy), which can reduce the overall thermal conductivity.…”

Section: Resultsmentioning

confidence: 99%

“…As one of the most fundamental material parameters, GB energy has a great impact on a variety of properties, including thermal conductivity, thermal resistance, fracture toughness, and fission gas release. 47 For example, GBs often scatter phonons (vibration quanta that carry heat energy), which can reduce the overall thermal conductivity. Higher GB energy, which usually means more defects and misorientations, can lead to increased phonon scattering and lower thermal conductivity.…”

Section: Using Dissimilarity Indexmentioning

confidence: 99%

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Quantifying Local Atomic Distortions in UO₂ Grain Boundaries: Correlation with Energetic and Electronic Properties

Zheng,

Wang,

Chen

et al. 2023

Inorg. Chem.

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UO 2 , as a key material in the nuclear industry, is composed of grains or crystallites in real applications. Their interfaces, known as grain boundaries (GBs), significantly impact thermal conductivity, corrosion resistance, and mechanical response. Here, utilizing Hubbard-corrected density functional theory, we systematically examine the local cluster structures, energetic stabilities, and electronic properties of five typical tilt UO 2 GBs ranging from Σ 3 to Σ 11. We categorize all possible distorted U-and O-centered clusters at these GBs and identify their cluster morphologies and radial and angular distortions. Our results highlight the abundance of new U−O bonds stretching to "medium-range", a feature often overlooked in conventional coordination analysis. To quantitatively describe these distorted clusters, we use smooth overlap of atomic positions (SOAP) to represent the structural and chemical local environments, which takes into account both radial (2-body) and angular (3-body) distortions. We define a dissimilarity index by computing the inner product of SOAP descriptors between the distorted and the perfect motif in ideal UO 2 . Our findings show that the medium-range SOAP dissimilarity correlates well with the GB excess energy, outperforming metrics such as dangling bonds or bonding strain. Furthermore, it is found that the band gaps in sufficiently high-energy GBs are shortened, with excess states primarily contributed by the distorted U clusters. Our results present a comprehensive gallery of the local distorted clusters introduced by typical UO 2 GBs and have implications on the structure−property relations of GBs and other interfaces.

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Section: Resultsmentioning

confidence: 99%

Section: Using Dissimilarity Indexmentioning

confidence: 99%

Quantifying Local Atomic Distortions in UO₂ Grain Boundaries: Correlation with Energetic and Electronic Properties

Zheng,

Wang,

Chen

et al. 2023

Inorg. Chem.

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“…The rare earth element cerium (Ce) has physicochemical properties and an electronic layer structure similar to those of U and Pu [6][7][8]. Furthermore, Ce is non-radioactive, making it an ideal simulation element for nuclear engineering [6,9,10]. Ce can be used in the preparation of nuclear simulated carbides.…”

Section: Introductionmentioning

confidence: 99%

Carbothermal reduction assisted by hydrogenation treatment for preparing single-phase CeC₂ nanoscale powders

Liu,

Lian,

Liu

2024

Mater. Res. Express

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Single-phase CeC2 powders can be successfully prepared through the carbothermal reduction assisted by hydrogenation treatment (CRHT) using 20-50 nm CeO2 as cerium source and 100-200 nm carbon black as carbon source. During the hydrogenation process, the interaction of CeO2 with H2 leads to a partial valence reduction of Ce ions, yielding a partially anoxic phase (CeO1.675) and a hydrogenated phase (CeH2). CeO1.675 can increase the oxygen vacancies required in the reaction process, while CeH2 can produce gas-phase reductant H2 at the reaction temperature, which together promotes the reduction reaction. The results show that the CRHT can obtain single-phase CeC2 powders at a temperature of 1550 ℃, which is 100 ℃ lower than its theoretical temperature. For the preparation of CeC2 powders, the CRHT is a low-temperature and efficient method.

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“…[ 1 ] It is widely used in coating, [ 2 ] catalysis [ 3 ] and solid oxide fuel cells. [ 4 ] Moreover, CeO 2 polishing powders are extensively used in chemical mechanical polishing (CMP) processing in the optical lens and semiconductor industries because of their remarkable selectivity and polishing efficiency. [ 5 ] The microstructure, particle size, mechanical properties, chemical reactivity, and crystal structure of CeO 2 abrasives are known to directly influence both the material removal rate and surface quality.…”

Section: Introductionmentioning

confidence: 99%

Influence of Cerium Oxide Abrasive Particle Morphologies on Polishing Performance

Ni,

Fan,

Chen

et al. 2024

Cryst. Res. Technol.

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In this study, two morphologies of cerium oxide (CeO2) abrasive particles, octahedral and spheroidal, are synthesized by solvothermal method using cerium nitrate hexahydrate (Ce(NO3)3‐6H2O) as raw material. Fourier infrared spectroscopy, X‐ray diffractometer (XRD) and scanning electron microscopy (SEM) are used to characterize the composition and morphology of CeO2 abrasive particles. The synthesized CeO2 is used for chemical mechanical polishing (CMP) of the Si surface of 6H‐SiC wafers, and the surface morphology of the polished wafers are observed using atomic force microscopy (AFM). After polishing with octahedral and spheroidal abrasive particles, the surface roughness of the wafers are 0.327 and 0.287 nm, and the material removal rates (MRR) are 870 and 742 nm h−1, respectively. Calculations comparing the ultraviolet absorption spectra and bandgap energies of the two types of abrasive particles as well as molecular dynamics (MD) simulations reveal that the synthesized octahedral CeO2 particles possessed stronger surface chemical activity and material removal performance.

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A molecular dynamics survey of grain boundary energy in uranium dioxide and cerium dioxide

Cited by 11 publications

References 51 publications

Quantifying Local Atomic Distortions in UO₂ Grain Boundaries: Correlation with Energetic and Electronic Properties

Quantifying Local Atomic Distortions in UO₂ Grain Boundaries: Correlation with Energetic and Electronic Properties

Carbothermal reduction assisted by hydrogenation treatment for preparing single-phase CeC₂ nanoscale powders

Influence of Cerium Oxide Abrasive Particle Morphologies on Polishing Performance

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A molecular dynamics survey of grain boundary energy in uranium dioxide and cerium dioxide

Cited by 11 publications

References 51 publications

Quantifying Local Atomic Distortions in UO2 Grain Boundaries: Correlation with Energetic and Electronic Properties

Quantifying Local Atomic Distortions in UO2 Grain Boundaries: Correlation with Energetic and Electronic Properties

Carbothermal reduction assisted by hydrogenation treatment for preparing single-phase CeC2 nanoscale powders

Influence of Cerium Oxide Abrasive Particle Morphologies on Polishing Performance

Contact Info

Product

Resources

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Quantifying Local Atomic Distortions in UO₂ Grain Boundaries: Correlation with Energetic and Electronic Properties

Quantifying Local Atomic Distortions in UO₂ Grain Boundaries: Correlation with Energetic and Electronic Properties

Carbothermal reduction assisted by hydrogenation treatment for preparing single-phase CeC₂ nanoscale powders