Radiation damage behavior of amorphous SiOC polymer-derived ceramics: the role of in situ formed free carbon

Free carbon networks (FCN) in situ formed in the amorphous SiOC polymer-derived ceramics (PDCs) have been reported to have significant effects on the material microstructures as well as the related structural and functional properties. In this paper, detailed effects of the FCN on the radiation damage process and mechanisms of the amorphous SiOC PDC are investigated by using ab initio molecular dynamics simulations. The radiation simulations were conducted by introducing a random Si atom with kinetic energy of 80 eV as the primary knock-on atom. The FCN are proven to be beneficial to absorb the ion induced kinetic energy and convert it into thermal spike, which can be dissipated as thermal energy. The FCN interfaces with Si-O-C matrix can also capture the displaced atoms easily, thus reducing the cascade damage. The SiOC PDC is promising to be radiation tolerant materials for the prevention of radiation defect accumulation by the contained amorphous phase and FCN structure. (C) 2020 Elsevier B.V. All rights reserved.