New findings related to carbothermal reduction of polysiloxane-derived ceramics

H Chaney and K Lu, CERAMICS INTERNATIONAL, 49, 10193-10197 (2023).

DOI: 10.1016/j.ceramint.2022.12.273

Carbothermal reduction is the primary mechanism for SiC formation in polymer derived ceramics. However, the specific process involved in the SiOC conversion to SiC and the role of oxygen and carbon are unknown. Using ReaxFF with LAMMPS in a large simulation system containing more than 93 K atoms, this study for the first time shows that O must be removed from SiO2 clusters for SiC formation, providing insights into the carbothermal reduction mechanism. SiO2 regions need to be of a large enough size to induce O reduction. C cluster growth is inversely related to removal of O. This work shows not only the importance of the simulation system size in understanding atomic interactions but also absence of phase separation of SiOC to SiO2. Instead, SiO2 converts to SiC through C diffusion and O removal.

Return to Publications page