Annealing of ion irradiation damage in nuclear graphite

Repair of defects created by Ar+ sputtering on graphite surface by annealing as confirmed using ToF‐SIMS and XPS

“…Highly oriented pyrolytic graphite (HOPG), which is produced by pyrolysis of a carbonaceous gas at high temperature, is considered defect‐free, but defects can be created on the surface of HOPG by sputtering the surface with an ion beam . Studies have shown that defects on graphite and graphene surfaces can be repaired under a carbon atmosphere, a noble gas atmosphere, or in the vacuum . The repairs can improve their thermal and electrical conductivities and enhance their mechanical strength .…”

“…10 Studies have shown that defects on graphite and graphene surfaces can be repaired under a carbon atmosphere, a noble gas atmosphere, or in the vacuum. [11][12][13][14][15][16][17][18][19] The repairs can improve their thermal and electrical conductivities and enhance their mechanical strength. 7,12 Cheng's group reported using an O 2 plasma to sputter the surface of HOPG at 90°C and then increased the sizes of the resulting defects to 10 to 20 nm with an H 2 plasma at 525°C.…”

Mesoscopic structure features in synthetic graphite

“…Most areas on the fracture surface show the morphology labelled "B" and only small regions are characteristic of those labelled "F". The flat "F" regions are exposed pre-existing cracks within filler particles [21], and are unaffected by the fracturing of the specimen. Voids exist everywhere, but it is difficult to differentiate those formed during manufacture from those generated by dislodging of fillers during fracture.…”

Edge-on dislocation loop in anisotropic hcp zirconium thin foil

“…Moreover, it is extremely hard to handle the neutron irradiated samples due to radioactivity. Ion irradiation experiments have been established as an alternate to neutron irradiation for the simulation of neutron irradiation effects in nuclear materials [10,17], which allows studying irradiation damage in nuclear structural materials without the need to deal with radioactive materials [18]. Additionally, higher defects accumulation within the samples can be achieved in relatively short times with light or heavy ion irradiation.…”

“…In literature, wide range of ion irradiation experiments are performed for studying irradiation defects evolution in materials, using ions from noble gases such as Ar, He or Xe and Kr [18e26]. The main differences between ion irradiation and neutron irradiation are: a) the larger size of the colliding particle compared to neutrons (Ar þ ions of 39 molecular weight are very frequently used, and are gigantic compared to the molecular weight of a neutron); b) the charge (neutrons have no charge) and the lower energies applied (usually ions have energies of the range from a few keV to a few hundreds keV, while neutrons reach higher energies up to 10 MeV in a fission system or 14 MeV in a fusion system) [18]. The main advantage of in-situ ion irradiation is that the damage evolution process can be continuously observed at different dose levels [8].…”