低温水热合成高纯硅酸锆粉体(英文)

以氧氯化锆和硅酸乙酯为原料,以NaF为矿化剂降低合成温度.采用水热法在160～240℃合成了高纯的ZrSiP4粉体.用X射线衍射、扫描电镜和能谱仪表征了ZrSiO4粉体的物相组成和显微结构.用氮气等温吸附Brunauer-Emmett-Teller法测试了ZrSiO4粉体的表面积和孔结构.结果表明:当F与Zr的摩尔比为2时,ZrSiO4的结晶温度可降低到160℃.ZrSiO4粉体为纳米纤维组成的椭球,大小约为1 μm.探讨了ZrSiO4粉体的形成机制和F离子的降低结晶温度的作用,F离子可以代替O离子形成Zr-F和Si-F键,降低形成ZrSiO4的能量势垒,促进了ZrSiO4的结晶.

LOW TEMPERATURE SYNTHESIS OF HIGH-PURITY ZIRCON POWDER BY A HYDROTHERMAL METHOD

High-purity zircon powders were prepared using zirconium oxychloride and tetraethoxysilane as starting materials by the hydrothermal method at 160-240℃ for 4 h.NaF was added to the gel as mineralizer to promote crystallization of zircon.The phase composition and microstructure of zircon powders were identified by X-ray diffraction,scanning electronic microscopy and energy dispersive X-ray spectroscopy.The surface area and pore structure were measured by N2 adsorption using the Brunauer-Emmett-Teller method.The results show that the starting crystallization temperature of zircon powder Can be decreased to 160℃ with an F to Zr mole ratio of 2.The zircon powders were ellipsoids composed of nanofibers with the size of about 1 μm.The formation mechanism and effect of F ions on lowering the crystallization temperature of zircon were investigated.When F ions replaced O ions.Zr-F and Si-F bonds can be formed.and it can lower the forming energy potential of zircon and promote the crystallization of zircon.