【摘要】 以正硅酸乙酯为硅源,采用两步溶胶-凝胶法结合超临界干燥技术制备出了块状无裂纹SiO2气凝胶,体积密度在50kg.m-3和300 kg.m-3之间,样品尺寸约为300mm×300mm×50mm。热学测试表明,常温常压下体积密度大约为100kg.m-3的样品导热系数为0.020 W/m.K,并采用XRD、SAXS、BJH和SEM等其他方法对典型样品(100kg.m-3)进行了测试。测试结果表明,SiO2气凝胶是非晶态的,并且具有纳米多孔结构(骨架颗粒平均粒径为6.8nm,孔径主要集中在10~20nm范围内,而且所有孔径都在70nm以内)。因而可作为具有一定潜在应用价值的块状纳米孔超级绝热材料。更多还原

【Abstract】 Monolithic silica aerogels of crackfree which were from tetraethoxysilane were prepared by two-step sol-gel process and supercritical drying technique.their densities are in the range of 50～ 300kg·m^-3 and their sizes are about 300×300×50mm³.The thermal conductivity measurement of the material(100 kg·m^-3) is 0.020 W/m·K at normal temperature and pressure,and is also tested by using XRD,SAXS,BJH,SEM and some other experimental techniques.The test results showed that the silica aerogel was non-crystalline,and it had nanosized porous structure（the mean diameter of skeletal particles was 6.8nm,a fairly uniform pore size distribution was in the range of 10～20nm and all poresˊsize is less than 70nm）.So they can be used currently and potentially as nonporous superthermal insulation materials.更多还原