One‐pot synthesis and polymer‐to‐ceramic transformation of a novel HfC precursor

Abstract In this study, a novel single‐source‐precursor HfMQ containing functional C═C and ─OH groups, was synthesized by a simple one‐pot synthesis strategy with hafnium tetrachloride, methacrylic anhydride, and hydroquinone as raw materials. The synthesis and polymer‐to‐ceramic transformation of the single‐source‐precursors were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance ( 1 H NMR and 13 C NMR), and thermogravimetric analysis, and the phase composition and microstructural evolution of the ceramics were characterized by X‐ray diffraction, Raman spectroscopy, transmission electron microscopy, and elemental analysis. The results show that the single‐source‐precursor HfMQ possesses the high ceramic yield of 58.98 wt.% at 1500°C among all the oxygen‐containing hafnium carbide (HfC) precursors reported in recent years, attributed to the improved cross‐linking involving (1) condensation reaction (OH/OH) and (2) addition reaction (C═C/═C) by introduction of C═C and OH groups into the HfMQ. The cross‐linked HfMQ is first transformed into HfO 2 at 600°C, and then completely into HfC at 1400°C by carbothermal reaction, with a Hf content higher than 85 wt.%. Due to the simple synthesis strategy, excellent solubility and high ceramic yield, the present HfMQ precursors have to be considered as promising impregnating agents for the preparation of HfC‐based ceramic matrix composites and HfC‐modified C/C composites by polymer impregnation and pyrolysis method, which makes them important candidate materials for aerospace vehicles and rocket thermal protection systems.