稀土掺杂氧化钛基材料的相变及其湿度-电阻关系

Transformation and Relations of Humidity-resistance of RE-doped TiO_2 Based Materials

本工作采用溶胶-凝胶工艺制备了La3+和Ce4+掺杂的TiO2-SnO2复合粉体,利用X-衍射仪对该粉体的相组成进行了分析,并对组装的湿敏薄膜元件进行了湿度-电阻关系的测试。结果表明,在500℃烧结,La3+和Ce4+掺杂对锐钛矿向金红石的转变起到先促进后阻碍的作用;600℃烧结,La3+和Ce4+掺杂抑制了锐钛矿向金红石的转变,La3+、Ce4+的加入降低了锐钛矿和金红石的晶体尺寸,同时降低了薄膜材料的电阻,使湿度-电阻关系呈现较好的线性度。La3+的作用最强,且促进了SnO2晶体的形成。

La^3＋ and Ce^4＋ doped TiO2-SnO2 powder were prepared by the sol-gel method. The phase compositions of powder were examined by XRD and the humidity-electric resistance relations were tested for the installed humidity film-sensing assemblies. Experimental results show that with the increase of La^3＋ and Ce^4＋ content, the transformation of anatase to rutile is first improved and then depressed when sintered at 500℃ and depressed when sintered at 600℃. La^3＋ and Ce^4＋ doping decreased the grain size of anatase and ruffle as well as the electric resistance of TiO2 based film, presenting better linearity in the humidity sensitivity relations. Moreover, the effect of La^3＋ doped is stronger than Ce^4＋ doped, and it stimulates the transformation of SnO2 phase.