Synthesis of nano-crystalline ZrB_2/ZrC/SiC ceramics by liquid precursors

摘要

ZrB_2/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 ℃ in argon led to formation of the nano-crystalline ZrB_2/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 β-silicon carbide phases. The average size of the ZrB_2, 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 ZrB_2 at 1000 ℃.