Liquid single-source-precursor synthesis and phase evolution of SiC-HfC-C ceramics nanocomposites with core-shell structured SiC@C and HfC@C nanoparticles

Liquid polymeric precursors have found wide applications as a matrix source for continuous fiber reinforced ceramic matrix composites (CMCs) because of their excellent fluidity and high ceramic yield. In the present study, a processable liquid single-source-precursor was synthesized using allylhydropolycarbosilane (AHPCS) and low-cost hafnium tetrachloride (HfCl₄) as raw materials to form final SiC-HfC-C nanocomposites by well-known polymer-derived ceramic (PDC) approach. The precursor synthesis, thermal behavior, polymer-to-ceramic transformation and ceramic phase evolution were investigated by FT-IR, TGA, XRD and TEM. The TGA results show that the obtained single-source-precursor exhibits very high ceramic yields of over 80.0 wt% after heat treated at 1400 °C. After annealing at 1600 °C, the resultant SiC-HfC-C nanocomposites contain SiC@C and HfC@C nanoparticles with SiC and HfC as cores and amorphous carbon as shells. The present single-source-precursor is candidate material for CMC applications due to its liquidity and high ceramic yield.