4. Conclusions
ZrB2 nanoparticles were synthesized by sol–gel method using AcOH as both chemical modifier and solvent to control Zr(OPr)4 hydrolysis in the absence of water for the starting materials. It is notable that a single phase ZrB2 could be obtained with a molar ratio of B/Zr=2.3 for the starting materials at 1550 °C for 2 h. Sphere-like, particle chain, and rod-like ZrB2 particles could be obtained synthesized at different gelation temperatures: 65, 75, and 85 °C. In an effort to understand the mechanism of morphology evolution, the “oriented attachment mechanism” might explain the crystalline processes of ZrB2 particles based on the HRTEM observation.