纳米孔莫来石陶瓷材料的制备

摘要

The silica aerogels composited with alumina nano-particles were prepared by sol-gel method and supercritical drying technique, using TEOS and alumina nano-particles as the precursors. The nanoporous mullite materials were obtained by the calcination of the aerogel monoliths at 1 200 and 1 300 ℃, and were characterized by means of XRD, FESEM and mercury porosimetry. The results of XRD indicate that mullitization appears after calcination at 1 200 ℃. The results of mercury porosimetry and FESEM show that mullite ceramic materials possess porous microstructure with the pore size of 200 -400 nm and 6 ~30 nm. Owing to the mullitization, the porous microstrcture of mullite ceramic materials has higher thermal stability.%以正硅酸乙酯(TEOS)提供硅源、纳米氧化铝(d90=50 nm)提供铝源,通过溶胶-凝胶法与超临界干燥技术,制备了分散纳米氧化铝的SiO2气凝胶块体,所得复合气凝胶块体经1 200℃、1 300℃热处理后,得到了纳米孔莫来石陶瓷材料.XRD测试表明:凝胶体在1 200℃热处理后发生了莫来石化,1 300℃莫来石化基本完成.压汞仪与场发射扫描电镜结果显示:凝胶块体经1 200、1 300℃热处理后,形成了具有纳米多孔结构的莫来石陶瓷材料,其骨架结构包含有200～400 nm的大孔,以及大量位于其孔壁上的6～30 nm的介孔.由于莫来石化的进行,热处理后的陶瓷材料的纳米孔结构具有更高的热稳定性.