Improvement of Thermal Stability of Porous Nanostructured Ceramic Membranes
Improvement of Thermal Stability of Porous Nanostructured Ceramic Membranes
复制标题
多孔纳米结构陶瓷膜热稳定性的提高
DOI：
10.1021/ie00028a012
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发表时间：
1994
影响因子：
4.2
通讯作者：
R. Gopalan
中科院分区：
文献类型：
--
作者：
Y. S. Lin;Chih;R. Gopalan
采用溶胶-凝胶法制备了无支撑无裂纹的氧化镧掺杂的氧化铝和氧化钛膜以及氧化钇掺杂的氧化锆膜。采用一种新的溶液-溶胶掺杂方法将掺杂剂氧化物涂覆在这些纳米结构陶瓷膜的颗粒表面。在空气和蒸汽/空气混合物气氛下从450 ℃至1,100 ℃热处理后，这些膜的孔和相结构数据显示这些掺杂陶瓷膜的热稳定性和水热稳定性显著改善。掺杂氧化镧（在[γ]-氧化铝和二氧化钛膜中）和氧化钇（在氧化锆膜中）将[γ]-氧化铝到[α]-氧化铝、金红石到金红石和四斜氧化锆到单斜氧化锆的相变温度分别提高了约200 ℃（对于氧化铝）、150 ℃（对于二氧化钛）和300 ℃（对于氧化锆）。在低于相变温度的温度下，掺杂延缓了三种膜的表面积损失和孔生长。对于所研究的三种陶瓷膜，稳定孔结构的效果按以下顺序降低：氧化锆>二氧化钛> [γ]-氧化铝。
Unsupported crack-free lanthana-doped alumina and titania membranes and yttria-doped zirconia membrane were prepared by the sol-gel method. A novel solution-sol doping method was employed to coat the dopant oxide on the grain surface of these nanostructured ceramic membranes. The pore and phase structure data of these membranes after heat treatment from 450 to 1,100 C under an atmosphere of air and a steam/air mixture show a substantially improved thermal and hydrothermal stability of these doped ceramic membranes. Doping lanthana (in [gamma]-alumina and titania membranes) and yttria (in zirconia membrane) raises the [gamma]-alumina to [alpha]-alumina, anatase to rutile, and tetragonal zirconia to monoclinic zirconia phase transformation temperature by about 200 C (for alumina), 150 C (for titania) and 300 C (for zirconia), respectively. At temperatures lower than the phase transformation temperatures, doping retards the surface area loss and pore growth of the three membranes. For the three ceramic membranes investigated, the effects of stabilizing the pore structure decrease in the following order: zirconia > titania > [gamma]-alumina.