Effects of ion irradiation on microstructures and mechanical properties of SiOC nanocomposites

SiOC polymer-derived ceramics (PDCs) are commonly used materials for advanced structural and functional applications. Especially, when in the form of fibers, they are used in the SiCf/SiC composites that is being considered an option for fuel cladding components in the current and next-generation light water reactors. But the radiation effects of the SiOC PDCs have been rarely reported (mostly focused on SiC). Here we prepared SiOC nanocomposites consisting of β-SiC nanocrystals and turbostratic graphite embedded in amorphous SiOC matrix, and irradiated them at room temperature with 4 MeV Kr ions to different damage levels. The irradiation-induced changes in the microstructures, surface morphologies, and mechanical properties were studied. It is indicated much severer irradiation condition leads to higher rearrangement degree of Si-containing tetrahedral units in the amorphous SiOC matrix, higher disordering degree of the turbostratic graphite, but crystallinity of the β-SiC is preserved. No obvious change is detected in the macro properties such as surface morphologies and mechanical properties (hardness and modulus). This study indicates the potential of SiOC PDCs to radiation damage.