Computational Screening of Dopants for Gas Suppression and Thermoelastic Response in PCS‐Derived SiC

ABSTRACT

H ₂ /CH ₄ evolution during polycarbosilane (PCS) pyrolysis generates microdefects that impair densification, while dopant‐induced changes in the derived SiC further affect its thermoelastic compatibility. Here, we develop a descriptor‐based computational screening framework to evaluate dopants for simultaneous gas‐suppression tendency in PCS and thermoelastic regulation of PCS‐derived SiC ceramics. Both substitutional and non‐substitutional doping scenarios were considered, and the latter was selected for systematic screening because it is considered more representative of practical precursor modification within the present descriptor‐based screening framework. The screening identifies 13 promising dopants, among which B, Hf, Zr, Re, and Os exhibit strong radical‐trapping capability and positive thermodynamic suppression of H ₂ /CH ₄ formation. Molecular dynamics simulations further suggest dopant‐ and concentration‐dependent changes in free volume, Young's modulus, Poisson's ratio, thermal expansion, and thermal‐mismatch risk. Within the present computational framework, Ta‐10% and Os‐10% are predicted as priority candidates that offer favorable trade‐offs between gas‐suppression descriptors and thermoelastic compatibility, with Hf‐10%, Zr‐5%, and Re‐3% emerging as secondary candidates for further validation.