Synthesis of nano-crystalline ZrB2/ZrC/SiC ceramics by liquid precursors

ZrB2/ZrC/SiC precursors were prepared in a one-pot reaction of polyzirconoxanesal with boric acid and poly (methylsilylene)ethynylene. The pyrolysis of the precursors at 1400 degrees C in argon led to formation of the nanocrystalline ZrB2/ZrC/SiC ceramics. The ceramics were characterized by inductively coupled plasma (ICP), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the ceramics were mainly composed of zirconium diboride, zirconium carbide and beta-silicon carbide phases. The average size of the ZrB2, ZrC and SiC grains was approximately 100 nm. Elemental analysis showed that the molar ratio of crystal phases was ZrB2/ZrC/SiC = 2/1.35/1, and the total weight ratio of zirconium, boride and silicon was above 81% in the ceramics. The presence of SiC obviously restrained the oxidation of ZrC and ZrB2 at 1000 degrees C. (c) 2011 Elsevier B.V. All rights reserved.