纤维增强SiO2气凝胶隔热复合材料的制备及其性能

将无机陶瓷纤维与SiO2溶胶混合,经超临界干燥制备了SiO2气凝胶隔热复合材料。SiO2气凝胶纤细的骨架颗粒减少了固态热传导,纳米级孔减少了气体热传导和对流传热,同时无机陶瓷纤维减少了辐射传热。SiO2气凝胶复合材料具有良好的隔热性能,其200℃和800℃的热导率分别为0.017W/m.K和0.042W/m.K。纤维的加入提供了力学支撑,高温处理增强了气凝胶骨架强度,材料在常温和高温下均具有良好的力学性能,其常温的拉伸、弯曲和抗压强度分别为1.44MPa、1.31MPa和0.98MPa(10%应变),800℃的拉伸、弯曲和抗压强度分别为1.95MPa、1.80MPa和1.42MPa(10%应变)。

Preparation and Properties of Fiber Reinforced SiO2Aerogel Insulation Composites

SiO_2 aerogel insulation composites were prepared by using ceramic fibers as reinforcement via supercritical drying process. Due to the ultra fine skeleton particles and nano-porous structure, silica aerogels have low gas thermal conductivity and solid thermal conductivity, and ceramic fibers greatly decrease radioactive thermal conductivity. Silica aerogel composites show excellent thermal insulation properties. The thermal conductivities at 200℃ and 800℃ are only 0.017W/m·K and 0.042W/m·K, respectively. The strength of the aerogel skeleton is enhanced by high temperature heat treatment, and with the reinforcement of fibers, the aerogel composites exhibit good mechanical property. The tensile, bending and compressive strengths at ambient temperature are 1.44MPa, 1.31MPa and 0.98MPa (10%strain), respectively, and the tensile, bending and compressive strengths at 800℃ are 1.95MPa, 1.80MPa and 1.42MPa (10%strain), respectively.