Synthesis, characterization, and ceramization of a SiC–ZrC–C preceramic polymer precursor

A silicon- and zirconium-containing polymer precursor (PSZC) for SiC–ZrC–C ceramic was successfully synthesized by chemical reaction of phenol, paraformaldehyde, tetraethoxysilane, acetylacetone, and ZrOCl₂·8H₂O. The chemical structure, pyrolysis behaviors, and pyrolysis products of PSZC were characterized by the combination of FT-IR, ¹H-NMR, TG-DTG, XRD, Raman, SEM, and EDS. It indicates that the obtained PSZC might be Zr–O–Zr and Si–O–Si chain polymer connected by Si–O–Zr bond with hydroxymethyl phenol and acetylacetone as ligands. And the most probable reaction mechanism to form PSZC was proposed. Decomposition of PSZC is completed at 800 °C, and it gives amorphous carbon, SiO₂, and ZrO₂ with a yield of 70 %. During heat treatment, SiC forms at about 1500 °C, followed by the appearance of ZrC. Defects of the carbon are cumulated to the highest at 1500 °C. Further heating at 1800 °C induces highly crystallized ZrC, SiC ceramic, and structure-ordered carbon with a structure of ZrC and SiC particles uniformly distributed in the carbon matrix.