Sn^(2+)掺杂TiO_2凝胶相变过程

Effects of Sn^(2+)Doping on Phase Transformation of TiO_2 Gels

采用溶胶-凝胶法制备了Sn2+掺杂TiO2纳米粉体,利用TG-DTA和XRD分析对凝胶的相变过程进行了表征。研究结果表明,Sn2+掺杂显著抑制了锐钛矿和金红石晶粒的长大,使凝胶-锐钛矿转变和锐钛矿-金红石转变的温度呈现先增加后降低的变化趋势。随着Sn2+掺杂量的增加,对锐钛矿向金红石转变的影响呈现了先促进后抑制的作用,且在20ST试样之后的各个温度都发现了SnO2的存在。锡离子的价态变化对相变特征起到非常重要的作用。

Sn^2＋ doped TiO2 nanopowders were prepared by the sol-gel method. The effect of Sn^2＋doping on phase transtormauon oi TiO2 gels was investigated by the TG-DTA and XRD technique. The results show that Sn^2＋doping greatly depresses the growth of anatase and rutile crystals. The transformation temperatures of gel to anatase and anatase to rutile present the trend of first increase and then decrease with the increase of Sn^2＋ content. Sn^2＋ doping improves first, and then depresses the transformation of anatase to rutile at the same time. When the dopant arrives at 20wt%, SnO2 crystals exist in all sintering temperature. It will be noticed that the valence change in Sn^2＋→Sn^4＋ has an important effect on the transformation behaviors.