Understanding the Irradiation Behavior of Zirconium Carbide

Motta, Arthur T.; Sridharan, Kumar; Morgan, Dane; Szlufarska, Izabela

doi:10.2172/1097003

Cited by 8 publications

(5 citation statements)

References 16 publications

(27 reference statements)

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“…This result was also consistent with other studies whose TEM analysis revealed amorphous carbon on the ~100 nanometre scale 24 . The extended network of intra and intergranular depressions as seen in the SEM images has also been observed in previous studies 12,15,19,24 . These features were seen to be comprised of sp 2 pristine, 'partially destroyed' graphite and amorphous carbon structures can be seen from the Raman spectra of samples produced in this study.…”

Section: Discussionsupporting

confidence: 87%

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

Rana

Solvas

Lee

et al. 2020

Sci Rep

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An investigation of the longrange and local structure of substoichiometric zirconium carbide sintered at different temperatures Dhan-sham B. K. Rana 1* , Eugenio Zapatas Solvas 2 , William e. Lee 2 & ian farnan 1 Zrc 1−x (sub-stoichiometric zirconium carbide), a group IV transition metal carbide, is being considered for various high temperature applications. Departure from stoichiometry changes the thermo-physical response of the material. Reported thermo-physical properties exhibit, in some cases, a degree of scatter with one likely contributor to this being the uncertainty in the C/Zr ratio of the samples produced. Conventional, methods for assigning C/Zr to samples are determined either by nominal stochiometric ratios or combustion carbon analysis. In this study, a range of stoichiometries of hotpressed ZrC 1−x were examined by SEM, XRD, Raman spectroscopy and static 13 C NMR spectroscopy and used as a basis to correct the C/Zr. Graphite, amorphous, and ZrC 1−x carbon signatures are observed in the 13 C NMR spectra of samples and are determined to vary in intensity with sintering temperature and stoichiometry. In this study a method is outlined to quantify the stoichiometry of ZrC 1−x and free carbon phases, providing an improvement over the sole use and reliance of widely adopted bulk carbon combustion analysis. We report significantly lower C/Zr values determined by 13 C NMR analysis compared with carbon analyser and nominal methods. Furthermore, the location of carbon disassociated from the Zrc 1−x structure is analysed using SEM and Raman spectroscopy. ZrC 1−x (sub-stoichiometric zirconium carbide), is under consideration for its use in generation IV nuclear fuel coatings due to its favourable mechanical, thermal, neutronic, and fission product retention properties 1-4. This combination of characteristics is derived from the combination of its metallic electronic properties and its ceramic properties 5. ZrC crystallises in the rocksalt structure with carbon atoms located in the octahedral interstitial sites. When carbon is removed from the ZrC structure, significant changes are seen in the physical and thermal properties. Scatter in reported data exists in the variation of the physical properties with the atomic C/Zr ratio. The scatter in the data potentially arises due to the combination of two factors: inaccurate composition measurements (C/Zr ratio) resulting in misreferenced physical properties; and the contribution of interstitial impurities such as oxygen and nitrogen leading to a range values for several themo-physical properties. Non-monotonic trends in material properties have been observed for physical properties, such as the lattice parameter. Assuming the sub-stochiometric material is comprised exclusively of ZrC and no contaminant species the configuration ordering of carbon atoms as the concentration of vacancies increases may be a contributing factor to the occurrence of these non-monotonic trends. As understanding of how these vacancies interact and how this affects material properties is c...

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Section: Discussionsupporting

confidence: 87%

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

Rana

Solvas

Lee

et al. 2020

Sci Rep

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“…Figure 10 shows the range of the predicted melting temperatures of Zr 4 C 4 in all high-pressure cases. The reported melting point of 3700 K [12,64] for Zr 4 C 4 at atmospheric pressure is within the scale of our prediction, shows that our calculation results for the melting temperatures of Zr 4 C 4 in other high-pressure cases are credible. The melting temperature of Zr 4 C 4 increases steadily at a rate from 12% to 5% in every increment of 10 GPa, indicating that the lowest melting point of Zr 4 C 4 is when it is under atmospheric pressure.…”

Section: Mechanical and Thermal Propertiessupporting

confidence: 85%

Pressure‐induced enhancement of mechanical performance in ZrC system

Yong

Chang

Low

et al. 2022

Int J of Quantum Chemistry

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Superhard materials are indispensable for use in cutting and polishing, as well as for nuclear reactor construction. As a candidate for hard material, ZrC has been extensively studied but not in its pressurized phase. Through evolutionary algorithm and density functional theory, we narrowed down the stoichiometry of Zr and C elements at various elevated pressures. The semimetal property of Zr4C4 continues to exist at high pressures but with lower electrical conductivity. Ionic and covalent bonding coexist around the pseudogap for high pressure phases. Both elastic constants and elastic moduli are found to increase steadily with surrounding pressure, connoting the superior mechanical and thermal characteristics of Zr4C4. This can be seen in the increased hardness values, higher melting temperatures, and better machinability indices for Zr4C4 as pressure rises. The predicted G/B and Poison's ratios have both agreed that Zr4C4 exhibits a transition from brittle to ductile behavior when the applied pressure goes above 85 GPa, displaying an overall improved mechanical performance.

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“…Examples include WC, whose hardness makes it useful in deep earth drilling, and ZrC, whose low nuclear cross section and resistance to fission products attack makes it an ideal coating for fuel particles in high temperature nuclear reactors. [1][2][3] TMCs have also been investigated as catalysts for hydrogen evolution and deoxygenation, [4][5][6][7] energy storage materials, [8][9][10] and as superconductors. [11][12][13] DOI: 10.1002/adts.202200439 TMCs resulting from the Group 4 (Ti, Zr, Hf) and Group 5 (V, Nb, Ta) transition metals tend to adopt the simple cubic rocksalt (NaCl-type) structure, where the metal and carbon atoms exclusively occupy separate fcc sublattices.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

First‐Principles Investigation of Phase Stability in Substoichiometric Zirconium Carbide under High Pressure

Thiel

Walsh

2022

Advcd Theory and Sims

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NaCl‐type carbides of the early transition metals can exhibit a substantial sub‐stoichiometry at the carbon site, impacting a host of bulk properties that depend upon carbon concentration including melting points, mechanical and elastic properties, and superconducting transition temperatures. Unfortunately, control over vacancies remains challenging with current preparation methods, motivating the search for new synthetic approaches that will allow for the prescription of specific vacancy configurations. Here, density functional theory is augmented with alloy cluster expansion to examine the structure and zero kelvin enthalpy of millions of structures across composition and pressure space. The results are used to examine how extreme pressures might be used to access novel ordered and disordered phases of ZrC, many of which have been calculated to be thermodynamically stable yet remain synthetically elusive. High pressure is shown to significantly reduce sub‐stoichiometry and drive the system toward fully stoichiometric ZrC. They examine the root of these changes and find that pressure exerts an influence over the distribution and abundance of specific nearest‐neighbor vacancy pairs. These results suggest that pressure is a powerful tool for the control of vacancies, and can offer a new synthetic handle on the bulk properties exhibited in this industrially important class of materials.

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Understanding the Irradiation Behavior of Zirconium Carbide

Cited by 8 publications

References 16 publications

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

Pressure‐induced enhancement of mechanical performance in ZrC system

First‐Principles Investigation of Phase Stability in Substoichiometric Zirconium Carbide under High Pressure

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