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

Abstract

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.