Mg^(2+)掺杂对TiO_2粉末晶型转变的影响与机理  

Effects of Mg^(2+) Doping on Polymorphic Transition of TiO_2 Powders and Mechanism

作　　者：王书亮[1] 刘洪学[1] 曾人杰[1] 

机构地区：[1]厦门大学化学化工学院材料科学与工程系,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2005年第6期806-809,共4页Journal of Xiamen University：Natural Science

基　　金：福建省自然科学基金(E0310005);武汉理工大学硅酸盐材料工程教育部重点实验室开放课题基金(2002)资助

摘　　要：取钛酸丁酯、无水乙醇和硝酸镁为原料,采用溶胶-凝胶法制备掺杂不同量Mg2+的TiO2粉末,用XRD、TEM、TG-DTA对粉末的晶体结构、晶粒大小和形貌进行表征,并研究了TiO2在锐钛矿型和金红石型之间的的晶型转变过程.结果表明:粉末的平均粒径为纳米级,当物质的量分数x(Mg2+/Ti4+)=1.0%,粉末平均粒径由60 nm左右减为40 nm左右;Mg2+的掺入延缓了TiO2由锐钛矿型向金红石型的转变,且随着Mg2+掺入量的增加,晶型转变越不容易发生,当物质的量分数x(Mg2+/Ti4+)=2.0%时,Mg2+在TiO2中的固溶度已经达到饱和,XRD谱图开始出现MgTi2O5的特征峰.分析了Mg2+的掺杂阻碍了TiO2由锐钛矿型向金红石型转变的原因.因此,掺杂适当量Mg2+有利于制备热稳定性比较高的锐钛矿型粉末.TiO2 powder which was doped with Mg^2＋ at different mole percent of x（Mg^2＋/Ti^4＋） was prepared by sol-gel routing and using Ti（OC4 H9 ）4 ,C2 H5 OH and Mg（NO3）2 as the raw materias. The structure size and appearance of powders were characterized by XRD,TEM and TG-DTA, and its polymorphie transition between anatase and rutile of TiO2 crystal type was also studied. The experimental results show that the average particle sizes of powders are in nanometer scale and the particle size at a mole percent of x（Mg^2＋/Ti^4＋） = 1.0% reduces to about 40nm while the particle size of TiO2 powder without Mg^2＋ is about 60nm; When the mole percent of x（Mg^2＋/Ti^4＋ ） =2.0% ,the solubility of Mg^2＋ in TiO2 reaches its saturation and the XRD spectrum of the powder has the character spectrum of MgTi2O5 ;Mg^2＋ doping can retard the transition of TiOz from anatase to rutile and the retarding effect is enhanced with increment of mole percent of x（Mg^2＋/Ti^4＋ ） The reason for the retarding effect is also analyzed;Therefore, proper mole percent of x（Mg^2＋/Ti^4＋ ） is useful to prepare TiO2 powders of anatase which has higher thermo-stability.

关 键 词：MG^2+ 掺杂 TIO2 粉末 晶型转变 

分 类 号：TB383[一般工业技术—材料科学与工程]