以正丙醇锆、硼酸、醋酸和D.果糖为原料,采用溶胶-凝胶法,结合高温碳热还原反应制备得到了长柱状单相ZrB2粉末。反应体系中,D-果糖不仅提供碳热还原反应的碳源,同时作为化学修饰剂,起到抑制正丙醇锆快速水解的作用。通过对比未陈化和陈化的凝胶制备得到的产物,探讨了陈化过程对于ZrB2粉末制备的影响。结果表明,凝胶陈化有利于ZrO2向ZrB2的完全转化。当起始原料满足n(B)/n(Zr)=3.5~4,n(C)/n(Zr)=7时,采用室温陈化7d的凝胶在1550℃保温2h可获得长度为4~7I.tm,横截面等效直径约为1岬1,长径比约为4~7,比表面积为2.53m。儋,D50=6.46μm的单相长柱状ZrB2粉末。
ZrB2 particles were synthesized by a Sol-Gel method using zirconium n-propoxide, boric acid, acetic acid and D-fructose. D-Fructose acts as both a modifier and a carbon source for carbothermal reduction reaction. For com- parison, both nascent state gel and aged gel were used to clarify the aging-time-dependent mechanism for ZrB2 synthe- sis. As a result, a single phase ZrB2 powder with a uniform size and shape distribution can be obtained from the aged gel with a boron and carbon to zirconium molar ratio of 3.5-4 and 7, respectively, after reduced at 1550 ~C for 2 h. Besides, the synthesized ZrB2 particles exhibit prism-like morphology with average particle size of ca. 4-7 pm in length, 1 μm in diameter of excircle of the cross-section and 4--7 in aspect ratio, when initial raw materials ratio n(B)/n(Zr) is 3.5-4 and n(C)/n(Zr) is 7. The median diameter Ds0 is 6.46 μm and specific surface area is about 2.53 m2/g. Furthermore, a complete carbothermal reduction of ZrO2 can be achieved using the aged gel.