氧化钇掺杂对Al_2O_3块状气凝胶结构与性能的影响

Effect on the Structure and Properties of Al_2O_3 Monolithic Aerogels Doped with Yttrium

以AlCl3·6H2O为原料,YCl3·6H2O为添加剂,采用溶胶-凝胶法和超临界干燥工艺制备得到氧化钇掺杂氧化铝块状气凝胶。其中掺杂含量控制在2.5wt%～30wt% Y2O3范围内。利用扫描电镜(SEM)、X射线衍射(XRD)、BET比表面积测定等测试手段对样品进行表征。结果表明:氧化钇的掺杂可以使氧化铝气凝胶在高温下维持高比表面积以及提高其在高温的热稳定性。经1000℃热处理后5.0wt% Y2O3-Al2O3气凝胶仍然处于无定形态,未发生相转变,比表面积仍达380～400m2/g,比纯Al2O3气凝胶(174m2/g)高出许多。

Yttrium doped alumina monolithic aerogels were prepared by sol-gel mothod and supercritical drying technique using AlCl3 · 6H2O as raw material,YCl3 · 6H2O as additive.The doping concentrations are in the range of 2.5wt%-30wt% Y2O3.The effect of yttrium doping on the structural and properties of alumina aerogels were characterizd by SEM,XRD,BET surface area.The results show that the surface area of Y2O3-Al2O3 aerogels was maintained large after heating at elevated temperatures.Improvements in thermal stability are obtained by incorporation of yttrium species during the aerogel preparation.When calcined at 1000 ℃,the 5.0wt% Y2O3-Al2O3 aerogel still showed the amorphous alumina and have larger surface area（380-400 m2 /g） than pure alumina aerogel（174 m2 /g）.