Preparation, cross-linking and ceramization of AHPCS/Cp2ZrCl2 hybrid precursors for SiC/ZrC/C composites

SiC/ZrC/C composites were prepared via pyrolysis of a polymeric precursor, namely AHPCS/Cp2ZrCl2 hybrid precursor prepared by the blend of allylhydridopolycarbosilane (AHPCS) and bis(cyclopentadienyl) zirconium dichloride (Cp2ZrCl2). The cross-linking and polymer-to-ceramic conversion of as-synthesized AHPCS/Cp2ZrCl2 were characterized by means of FTIR, 13C NMR, TGA, EDS, Raman spectroscopy and XRD. It is suggested that dehydrocoupling, hydrosilylation and dehydrochlorication are involved in the cross-linking of the hybrid precursor, which is responsible for a relatively high ceramic yield of 75.5% at 1200 °C. The polymer-to-ceramic conversion is complete at 900 °C, and it gives an amorphous ceramic. Further heating at 1350 °C induces partial crystallization, and then the characteristic peaks of β-SiC and cubic ZrC appear at 1600 °C. The effect of the composition of the hybrid precursor is also studied in the work.