热处理对纤维增强SiO2气凝胶性能的影响

采用溶胶一凝胶法制备了纤维增强SiO_2气凝胶隔热材料,对基体SiO_2气凝胶及复合材料进行不同温度的热处理.利用扫描电镜、比表面积和孔径测试仪和导热仪等手段对处理后材料的微观结构和常温隔热性能进行表征.结果表明:复合材料经低于700℃处理后,材料基体的微观结构略有变化,常温隔热性能基本保持不变;经1000℃处理的纳米结构发生了烧结、纳米孔含量减少,常温隔热性能显著降低.

InfluenceofHeatTreatmentonPropertiesofSilicaAerogels ReinforcedbyCeramicFibers

SiO_2 aerogels reinforced by ceramic fibers were prepared by sol-gel method. Both the SiO_2 aerogels and the composite were treated under different temperatures. SEM, N_2 adsorption-desorption and thermal conductivity device were adopted to characterize the structure and thermal conductivity properties of the prepared materials. The resuits show that the microstmcture changes little after heating under 700℃ and the heat insulation properties maintains almost unchanged. However, after heat treatment at 1 000℃ ,the heat insulation properties decreased,nano-microstructures sintered and the amount of pores reduced.