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

Abstract

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.

Kr ion irradiation study of polymer‐derived SiFeOC–C–SiC nanocomposite

“…The lower peak intensity of the Si–C bond means a smaller amount of SiC, while the high intensity of the O–Si–O bonds indicates the dominance of amorphous SiO 2 and other relevant SiOC tetrahedrals. The Si 2p spectra (Figure 6D) should also comprise various forms of SiO x C y between the SiO 4 and SiC 4 peaks, including SiO 2 C 2 , SiO 3 C, and SiOC 3 , 49 although they are not clearly observed based on the XPS peak deconvolution in Figure 6D. The high intensity of the overall peak demonstrates the dominance of the SiOC matrix.…”

Structural and thermodynamic analysis of metal filler incorporations in SiaOb(M)cCd polymer derived ceramics: Ta, Hf, Nb

“…[28][29][30][31][32] It is especially important to identify the effect of filler and corresponding structural modification on the thermodynamic stability of the respective ceramics, since stability determines propensity for phase separation and decomposition in PDCs. 5,[33][34][35][36][37] In the past, thermodynamic works investigated structure-stability relations in various PDC systems, including the effect of composition, mixed bonding, and pyrolysis temperature on the thermodynamic stability. 5,34,37 To this end, the present paper is the first work to systematically investigate the structural evolution and thermodynamic stabilization in PDCs incorporating Hf, Nb, and Ta.…”

“…As the use of PDC fillers increases, it is essential to understand how choice of filler influences composition as well as microstructure 28–32 . It is especially important to identify the effect of filler and corresponding structural modification on the thermodynamic stability of the respective ceramics, since stability determines propensity for phase separation and decomposition in PDCs 5,33–37 …”