ZrO_2–Al_2O_3复合气凝胶的制备与表征

Preparation and Characterization of ZrO_2–Al_2O_3 Composite Aerogels

以锆酸四丁酯、仲丁醇铝为原料,采用丙酮-苯胺原位生成水法结合乙醇超临界干燥技术制备了Zr O2-Al2O3复合气凝胶。利用扫描电子显微镜、氮气吸附-脱附比表面积与孔径分析仪和X射线衍射仪等对气凝胶的微观形貌、结构进行表征。结果表明：制得的Zr O2-Al2O3复合气凝胶比表面积为558 m2/g;1 000℃热处理后,比表面积仍高达129 m2/g,晶粒尺寸在7~14 nm之间;晶相从无定型态变为四方相氧化锆。通过纯Zr O2气凝胶与Zr O2-Al2O3复合气凝胶的对比发现,掺杂氧化铝可有效抑制氧化锆高温热处理过程中的晶体生长和晶相转变,提高耐温性能。

Zr O2-Al2O3 composite aerogel was prepared via acetone-aniline in situ water formation（ISWF） method with zirconium n-butoxide and aluminum tri-sec-butoxide as precursors, and subsequent alcohol supercritical drying. The morphology and structure of the aerogel were characterized by scanning electron microscopy, N2 adsorption analysis and X-ray diffraction, respectively. The specific surface area of obtained Zr O2-Al2O3 composite aerogel is 558 m2/g. The specific surface area is still 129 m2/g and its crystal size is 7-14 nm even after heat treatment at 1 000 ℃. The phase of aerogel is transformed from amorphous zirconia to tetragonal zirconia. Compared to Zr O2 aerogel with Zr O2-Al2O3 composite aerogel, doping with alumina can effectively restrain the crystal growth and phase transition of zirconia during high-temperature heat treatment, and improve the thermal insulation property.