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

Su, Qing; Ding, Hepeng; Price, Lloyd; Shao, Lin; Hinks, John; Greaves, Graeme; Donnelly, S. E.; Demkowicz, Michael J.; Nastasi, M.

doi:10.1038/s41598-018-23426-y

Cited by 13 publications

(13 citation statements)

References 53 publications

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“…In contrast to the high density of He bubbles in implanted Fe films, no helium bubbles (>1 nm) were observed in pure SiOC film after 5 at% He implantation, Figure 2c,d. This result was consistent with previous finding that He atoms in SiOC remain in solution and are able to outgas from the material via atomic-scale diffusion [15,28]. In addition, the irradiation does not lead to any void formation, element segregation or crystallization throughout the SiOC film.…”

Section: Resultssupporting

confidence: 92%

“…While the above discussion on interface design strategies have shown that it is possible to delay the deleterious effects of He, recent studies have shown that in some materials it is possible to avert helium bubble formation entirely by continually removing it as it is implanted [15]. Amorphous SiOC, a new class of superior radiation tolerant materials, has shown very good steady-state irradiation properties [16].…”

Section: Introductionmentioning

confidence: 99%

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Resistance to Helium Bubble Formation in Amorphous SiOC/Crystalline Fe Nanocomposite

Wang

Gigax

et al. 2018

Materials

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The management of radiation defects and insoluble He atoms represent key challenges for structural materials in existing fission reactors and advanced reactor systems. To examine how crystalline/amorphous interface, together with the amorphous constituents affects radiation tolerance and He management, we studied helium bubble formation in helium ion implanted amorphous silicon oxycarbide (SiOC) and crystalline Fe composites by transmission electron microscopy (TEM). The SiOC/Fe composites were grown via magnetron sputtering with controlled length scale on a surface oxidized Si (100) substrate. These composites were subjected to 50 keV He+ implantation with ion doses chosen to produce a 5 at% peak He concentration. TEM characterization shows no sign of helium bubbles in SiOC layers nor an indication of secondary phase formation after irradiation. Compared to pure Fe films, helium bubble density in Fe layers of SiOC/Fe composite is less and it decreases as the amorphous/crystalline SiOC/Fe interface density increases. Our findings suggest that the crystalline/amorphous interface can help to mitigate helium defect generated during implantation, and therefore enhance the resistance to helium bubble formation.

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Section: Resultssupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Resistance to Helium Bubble Formation in Amorphous SiOC/Crystalline Fe Nanocomposite

Wang

Gigax

et al. 2018

Materials

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“…This observation is consistent with our previous studies, where no He bubbles were observed in amorphous SiOC films subjected to an applied implantation dose of up to 113 at. % 13 , 19 . In contrast to the absence of He bubbles in the implanted SiOC film, the under-focused TEM micrograph of the implanted Fe film (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Another example of an amorphous material with unique irradiation/implantation stability is amorphous silicon oxycarbide (SiOC). Our previous studies on SiOC demonstrated that He bubble formation can be entirely averted due to the rapid diffusion of implanted ions out of the structure 13 , 19 . It was also demonstrated that amorphous/crystalline nanolaminates consisting of amorphous SiOC/crystalline α-Fe have desirable structural stability over a range of irradiation/implantation conditions (i.e., ion species, energy, and temperature) 20 – 23 .…”

Section: Introductionmentioning

confidence: 99%

Mechanical Response of He-Implanted Amorphous SiOC/Crystalline Fe Nanolaminates

Zare

Gigax

et al. 2019

Sci Rep

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This study investigates the microstructural evolution and mechanical response of sputter-deposited amorphous silicon oxycarbide (SiOC)/crystalline Fe nanolaminates, a single layer SiOC film, and a single layer Fe film subjected to ion implantation at room temperature to obtain a maximum He concentration of 5 at. %. X-ray diffraction and transmission electron microscopy indicated no evidence of implantation-induced phase transformation or layer breakdown in the nanolaminates. Implantation resulted in the formation of He bubbles and an increase in the average size of the Fe grains in the individual Fe layers of the nanolaminates and the single layer Fe film, but the bubble density and grain size were found to be smaller in the former. By reducing the thicknesses of individual layers in the nanolaminates, bubble density and grain size were further decreased. No He bubbles were observed in the SiOC layers of the nanolaminates and the single layer SiOC film. Nanoindentation and scanning probe microscopy revealed an increase in the hardness of both single layer SiOC and Fe films after implantation. For the nanolaminates, changes in hardness were found to depend on the thicknesses of the individual layers, where reducing the layer thickness to 14 nm resulted in mitigation of implantation-induced hardening.

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“…This model class of amorphous ceramics has exhibited great stability under irradiation, sustaining its glassy state over a wide range of irradiation conditions [14,15]. In addition, it has demonstrated the immunity of He bubble formation by continually removing He as it was implanted [16,17]. For instance, implanted He atoms were found to outgas from the SiOC matrix through atomic-scale diffusion without damaging its free surfaces, even at liquid nitrogen temperatures, resulting in time-invariant structure and properties.…”

Section: Introductionmentioning

confidence: 99%

Radiation Tolerance in Nano-Structured Crystalline Fe(Cr)/Amorphous SiOC Composite

Wang

Shao

et al. 2019

Crystals

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The management of irradiation defects is one of key challenges for structural materials in current and future reactor systems. To develop radiation tolerant alloys for service in extreme irradiation environments, the Fe self-ion radiation response of nanocomposites composed of amorphous silicon oxycarbide (SiOC) and crystalline Fe(Cr) were examined at 10, 20, and 50 displacements per atom damage levels. Grain growth in width direction was observed to increase with increasing irradiation dose in both Fe(Cr) films and Fe(Cr) layers in the nanocomposite after irradiation at room temperature. However, compared to the Fe(Cr) film, the Fe(Cr) layers in the nanocomposite exhibited ~50% less grain growth at the same damage levels, suggesting that interfaces in the nanocomposite were defect sinks. Moreover, the addition of Cr to α-Fe was shown to suppress its grain growth under irradiation for both the composite and non-composite case, consistent with earlier molecular dynamic (MD) modeling studies.

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

Cited by 13 publications

References 53 publications

Resistance to Helium Bubble Formation in Amorphous SiOC/Crystalline Fe Nanocomposite

Resistance to Helium Bubble Formation in Amorphous SiOC/Crystalline Fe Nanocomposite

Mechanical Response of He-Implanted Amorphous SiOC/Crystalline Fe Nanolaminates

Radiation Tolerance in Nano-Structured Crystalline Fe(Cr)/Amorphous SiOC Composite

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