Hydrogen enhances the radiation resistance of amorphous silicon oxycarbides

Ding, Hepeng; Demkowicz, Michael J.

doi:10.1016/j.actamat.2017.07.017

Cited by 12 publications

(8 citation statements)

References 98 publications

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“…The breaking and formation of the Si–O and Si–C bonds are mainly observed. The slight decrease in the number of Si–O bonds and increase in the Si–C bonds agree well with the literature . The breaking and formation of the Si–Si and C–C bonds are also observed, and their bond numbers are almost unchanged before and after ion irradiation.…”

Section: Resultssupporting

confidence: 91%

Radiation Effects in the Crystalline–Amorphous SiOC Polymer-Derived Ceramics: Insights from Experiments and Molecular Dynamics Simulation

Niu

Gao

Zhao

et al. 2021

ACS Appl. Mater. Interfaces

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Radiation-tolerant materials are in great demand for safe operation and advancement of nuclear and aerospace systems. Nanostructuring is a key strategy to improve the radiation tolerance of materials. SiOC polymer-derived ceramics (PDCs) are unique synthetic nanocomposites consisting of β-SiC nanocrystals and turbostratic graphite distributed in amorphous SiOC matrix, which are "all-rounder" materials for many advanced structural and functional applications. Radiation effects in the crystalline−amorphous system have been investigated in detail by experiments and molecular dynamics (MD) simulations. The results indicate that the amorphous SiOC structure retains amorphous accompanied by redistribution of the Si-containing tetrahedra. The graphite is shown to amorphize more easily than β-SiC nanocrystals under the same irradiation condition. The sample richer in oxygen, namely, containing more amorphous SiOC, shows less disordering of graphite, resulting from greater mitigation of radiation damage by the amorphous phase as efficient sinks. This study provides details of the microstructure evolution of SiOC PDCs under ion irradiation, as well as insights for the design and development of advanced ion damage-resistant materials.

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Section: Resultssupporting

confidence: 91%

Radiation Effects in the Crystalline–Amorphous SiOC Polymer-Derived Ceramics: Insights from Experiments and Molecular Dynamics Simulation

Niu

Gao

Zhao

et al. 2021

ACS Appl. Mater. Interfaces

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“…Previous investigations have shown that reliable atomistic models of SiOC must contain approximately 1500 atoms: a relatively large number for DFT calculations 12 , 33 . Thus, to optimize use of computational resources, we do not perform our calculations directly on SiOC models.…”

Section: Resultsmentioning

confidence: 99%

“…However, in both cases, their effect is small, indicating that the resistance of SiOC to He-induced damage does not depend crucially on composition. This finding is important for the continued development of radiation-resistant SiOC materials, as it suggests that their composition may be tuned to optimize other properties—such as thermal stability 33 or resistance to displacement damage 12 —without affecting their immunity to He. However, if the C concentration increases so much that the CRN structure begins to break down, we expect that the behavior of He in SiOC may undergo a qualitative change.…”

Section: Discussionmentioning

confidence: 99%

“…The former occurs when an atom in the material displaces permanently from its initial location due to a collision by an impinging particle. In crystalline solids, atom displacements generate vacancies and interstitials 11 while in network-bonded amorphous solids, like SiOC, they produce coordination defects such as dangling bonds 12 . While displacement damage disrupts the atomic-level structure of the material, it is potentially recoverable without long-range mass transport, e.g.…”

Section: Introductionmentioning

confidence: 99%

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Rapid and damage-free outgassing of implanted helium from amorphous silicon oxycarbide

Ding

Price

et al. 2018

Sci Rep

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Damage caused by implanted helium (He) is a major concern for material performance in future nuclear reactors. We use a combination of experiments and modeling to demonstrate that amorphous silicon oxycarbide (SiOC) is immune to He-induced damage. By contrast with other solids, where implanted He becomes immobilized in nanometer-scale precipitates, He in SiOC remains in solution and outgasses from the material via atomic-scale diffusion without damaging its free surfaces. Furthermore, the behavior of He in SiOC is not sensitive to the exact concentration of carbon and hydrogen in this material, indicating that the composition of SiOC may be tuned to optimize other properties without compromising resistance to implanted He.

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“…Further applications are reactions occurring during the deposition of low-κ dielectric SiCO/H materials, as well as thermal treatment of these materials (post or concurrent synthesis) in reactive atmospheres such as H 2 O, CO 2 , or H 2 . Future direction involves thermodynamic and kinetic stability of dielectric films, thermal conductivity, and the effects of radiation damage , or ion implantation . Obviously, force field development is an ongoing process with room for improvement and progress.…”

Section: Discussionmentioning

confidence: 99%

Reactive Force Field for Simulations of the Pyrolysis of Polysiloxanes into Silicon Oxycarbide Ceramics

2019

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We provide a new reactive force field (ReaxFF) for simulations of silicon oxycarbide (SiCO) ceramics and of their syntheses from inorganic polymer precursors. The validity of the force field is extensively tested against experimental and computational thermochemical data. Its performance in simulation at elevated temperatures is gauged by the results of comprehensive ab initio molecular dynamics simulations. We apply the force field to the formation of amorphous SiCO in a simulated polymer pyrolysis. Modeling results are in good agreement with experimental observations and allow new insights into the formation of graphene segregations embedded in an amorphous oxycarbide matrix. The new ReaxFF for Si–C–O–H compounds enables large-scale and long-time atomistic simulations with unprecedented fidelity.

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Hydrogen enhances the radiation resistance of amorphous silicon oxycarbides

Cited by 12 publications

References 98 publications

Radiation Effects in the Crystalline–Amorphous SiOC Polymer-Derived Ceramics: Insights from Experiments and Molecular Dynamics Simulation

Radiation Effects in the Crystalline–Amorphous SiOC Polymer-Derived Ceramics: Insights from Experiments and Molecular Dynamics Simulation

Rapid and damage-free outgassing of implanted helium from amorphous silicon oxycarbide

Reactive Force Field for Simulations of the Pyrolysis of Polysiloxanes into Silicon Oxycarbide Ceramics

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