Synthesis of ZrB₂ nanoparticles by using xylitol

ZrB₂ nanoparticles were synthesized synergistically by Sol-Gel method and carbothermal reduction reaction using zirconium n-propoxide, acetic acid, boric acid and xylitol as starting materials. In the reaction system, xylitol acted as a carbon source for the carbothermal reduction reaction and chelated boron, leading to the formation of coordination compound through its polyhydroxy reaction with boric acid. According to the Fourier Transform infrared spectra and thermal analysis of gel precursor, the effects of sol and gel reaction processes on the carbothermal reduction reaction temperature and gelation time were discussed. The results show that the polyhydroxy compound of xylitol is beneficial to initiate reactions and gelation, which makes the threshold throughout the whole chemical processes easy to overcome. The gel does not need aging treatment and the reaction temperature is lowered. Besides, a single phase of equiaxed ZrB₂ nanoparticles could be obtained from nascent state gel calcined at 1450℃ with n(xylitol)/n(zirconium n-propoxide) of 1.4. The average diameter and oxygen content of ZrB₂ nanoparticles are ca. 50 nm and 1.36wt%, respectively.