A meltable precursor for zirconium carbide ceramics and C/C-ZrC composites

For process simplification and rapid densification of ceramic composites, a meltable single-source ZrC precursor was prepared by condensing zirconium acetylacetonate (Zr(acac)4) at 190 °C for 40-150 min. The preparation of ZrC precursor and the conversion from precursor to ceramics were investigated by using FTIR and NMR spectroscopies, GPC, DSC-TGA, XRD, SEM, EDS and TEM. The precursor had low viscosity (~ 10 mPa s) and proper processing window (60 min) for precursor infiltration and pyrolysis (PIP). The ceramic yield at 1650 °C was 29.6%, and EDS revealed that the composition was (ZrC)0.337(HfC)0.0025(ZrO2)0.044C0.1865. The ceramics were composed of 0.2-0.5 µm grains which aggregated to form a stacked structure surrounded by amorphous carbon. The preparation processes were designed, and C/C-ZrC composites with the density of 2.45 g/cm3 were successfully fabricated through 11 cycles of PIP with Zr(acac)4. In conclusion, the synthetic method provides a simple and cheap route for precursors, and allows combined composite preparation with high efficiency.