【摘要】 以非离子型表面活性剂P123和三甲基苯的微乳液为模板剂合成介孔SiO2粉体.以此粉体为原料,经干压成型、烧结制备多孔SiO2块材.分别用AlOOH溶胶和TiO2溶胶包覆多孔SiO2粉体,制成多孔SiO2/Al2O3块材和SiO2/TiO2块材.采用XRD、SEM、TEM、N2吸附法和阿基米德排水法对所制粉体和块材进行了表征,并研究了块材的热稳定性.结果表明,600～700℃烧结的多孔SiO2基块材的孔隙率为74%～76%.与多孔SiO2块材相比,在800～1000℃范围内,SiO2/Al2O3块材的热稳定性显著提高,SiO2/TiO2块材的热稳定性在800～900℃范围内有一定改善.更多还原

【Abstract】 Porous monoliths with high porosity and improved high temperature stability are required in heat insula-tion.Mesoporous SiO2 powder was synthesized from tetraethyl orthosilicate using oil-in-water microemulsions composed of non-ionic surfactant P123 and 1,3,5-trimethylbenzene as template.Porous SiO2 monoliths were pre-pared from the mesoporous SiO2 powder by dry pressing followed by sintering.Porous SiO2/Al2O3 monoliths and SiO2/TiO2 monoliths were prepared from mesoporous SiO2 powders coated with boehmite Sol and titania Sol re-spectively.XRD,SEM,TEM,N2 adsorption and Archimedes method were employed to characterize the powders and the monoliths.The thermal stability of the monoliths was studied.The porosity of the silica-based monoliths sintered at 600-700℃ is about 74%-76%.Compared with SiO2 monolith,porous SiO2/Al2O3 monolith has much better thermal stability at 800-1000℃ and porous SiO2/TiO2 monolith has an improved thermal stability at 800-900℃.It is indicated that alumina coating on porous silica particle surface can improve the high temperature stability of SiO2/Al2O3 monolith.更多还原