微波水热法合成硅酸锆纳米粉体的研究

Preparation of Nano-ZrSiO_4 Powders by Microwave-Hydrothermal Method

以氧氯化锆和硅酸乙酯为原料、NaF为矿化剂,采用微波水热法(Microwave-hydrothemal,M-H)在160～200℃成功地制备出高纯硅酸锆纳米粉体,并利用X射线衍射(XRD)和扫描电镜(SEM)对所合成的硅酸锆粉体进行了研究,结果表明,微波水热使ZrSiO_4的结晶温度降低到160℃,合成时间缩短到30min,大大降低了硅酸锆粉体的合成能耗。硅酸锆的微波水热合成温度为180℃时,所合成的硅酸锆粉体颗粒呈圆片状,直径约为400nm,厚度约为直径的1/10,外形规则,粒度分布均匀。通过谢乐公式可以计算出微波水热法合成的ZrSiO_4晶体的尺寸约为20nm。煅烧有利于进一步提高粉体的结晶度,但是颗粒形状及大小均未产生显著变化。结合测试分析,对纳米硅酸锆粉体的微波水热合成反应机理进行了初步探讨。

High-pure zircon powders are prepared using zirconium oxychloride and tetraethoxysilane as staring materials by the microwave-hydrothermal method at 160-200℃ for 30min, NaF is added to gel as mineralizer to promote crystallization of zircon. The phase composition and mircostructure of zircon powders are identified by X-ray diffraction and SEM. The results show that microwave-hydrothermal method can greatly reduce the synthesis of zirconium silicate powder consumption by reducing the crystallization temperature of ZrSiO4 to 160℃ and the crystallization time to 30min. Zircon powders synthesized by microwave hydrothermal method are ellipsoids, The size and shape of particle do not change much after calcined at 950℃, the zircon crystal size reaches the maximum （20nm）. And the reaction mechanism of microwave hydrothermal synthesis of zirconium silicate is discussed.