Ceramization of Reflux-Treated Polymethylsilane Precursors to Silicon Carbide

The pyrolysis of polymethylsilane (PMS) in an argon gas environment with a flow rate of 1 L/min was investigated as a standard pyrolytic process, and the investigation showed SiSi network formation at 573 K. Subsequently, various condensed PMS resins were prepared by adjusting pre‐heat‐treatment or reflux conditions in the temperature range of 423–723 K. The effect of pre‐heat treatment or refluxing on the ceramic yield at 1273 K was quantitatively evaluated. Structural evolution in the PMS resins prepared under various reflux conditions was investigated during pyrolysis up to 1873 K. The X‐ray diffraction patterns of the pyrolysis products revealed crystallite growth of β‐SiC and silicon at 1273–1473 K. 29Si solid‐state nuclear magnetic resonance with the single‐pulse method was also conducted on the pyrolysis products at 1273 K.