Synthesis of ZrB₂-SiC composite powders by sol-gel method using acetic acid as chemical modifier

ZrB₂-SiC ceramics are known to have better performance than monolithic ZrB₂. Therefore, the addition of SiC can improve the mechanical properties and sintering behavior of ZrB₂. In the present work, ZrB₂-SiC composite powders were synthesized by sol-gel method using zirconium n-propoxide (Zr(OPr)₄), boric acid (H₃BO₃), sucrose (C₁₂H₂₂O₁₁), TEOS, and acetic acid (AcOH). Clearly, it was a non-aqueous solution system at the very beginning of the reactions. Here, AcOH was used as both chemical modifier and solvent to control Zr(OPr)₄ hydrolysis. Actually, AcOH could dominate the hydrolysis by self-produced water of the chemical propulsion, rather than the help of outer water. C₁₂H₂₂O₁₁ was selected since it can be completely decomposed to carbon. Thus, carbon might be accounted precisely for the carbothermal reduction reaction. Moreover, the photomicrograph revealed a spherical morphology of ZrB₂-SiC composite particles with an uniform size distribution.