Synthesis of hexagonal-prism-like ZrB₂ by a sol-gel route

One-dimensional (1D) materials can increase mechanical properties along the long axis of the reinforcement for the composites because of the transfer of stress across the reinforcement-matrix interfaces parallel with the load. In this study, 1D hexagonal-prism-like ZrB₂ particles were synthesized by a sol-gel route using zirconium n-propoxide, boric acid, acetic acid, and fructose. Fructose acted as both a modifier and a carbon source for carbothermal reduction reaction. For comparison purposes, both nascent state gel and aged gel were used to clarify the aging-time-dependent mechanism for ZrB₂ synthesis. As a result, a single phase ZrB₂ could only be obtained from the aged gel with the optimal ratios (by mol.) of 1.2 and 5 for both fructose and acetic acid to zirconium n-propoxide, respectively, reduced at an optimal temperature of 1550°C for 2h. Additionally, it revealed a perfect hexagonal-prism-like morphology for the ZrB₂ particles with a uniform size and shape distribution, and average particle size of ca. 0.8μm in diameter of excircle of the hexagonal cross-section.