Active chemical furnace‐assisted combustion synthesis of SiC nanoparticles with in situ spontaneous granulation

We report a novel combustion synthesis strategy assisted by a magnesium oxide (MgO)‐polytetrafluoroethylene (PTFE)‐based chemical furnace for the efficient preparation of high‐purity silicon carbide (SiC) nanoparticles and their in situ granulation into spherical micro‐agglomerates. The heat released by the MgO‐PTFE reaction serves as a localized thermal source to preheat the Si‐C mixture and simultaneously triggers a reaction between Si and gaseous C x F y intermediates produced from PTFE pyrolysis. This auxiliary gas–solid reaction not only provides additional heat but also significantly lowers the activation energy of the Si‐C reaction, thereby enabling a self‐sustaining combustion synthesis at relatively low temperatures. Furthermore, the synergistic effects of localized heating and reaction kinetics lead to the soft agglomeration of SiC nanoparticles into 10‐ to 30‐µm spherical agglomerates during the reaction process. This work provides a new approach for the scalable, low‐cost synthesis of nano‐SiC materials, while also revealing the critical role of gas‐phase intermediates in combustion synthesis and morphology evolution.