耐高温二氧化硅气凝胶复合材料制备及其导热研究

Preparation and Thermal Conductivity of High Temperature Silica Aerogel Composites

以二氧化硅溶胶为前驱体,利用树脂转移模塑成型(Resin transfer molding,RTM)工艺制备了二氧化硅气凝胶复合材料。对制备的气凝胶复合材料进行了结构表征;对气凝胶复合材料的隔热性能和耐高温性能进行了试验考核,结果显示,20 mm厚材料经过900℃、1000 s的石英灯考核后背温为186℃,材料经过1100℃、1000 s的马弗炉试验后线收缩率为1.2%,该气凝胶复合材料具有优良的隔热性能和耐高温性能。研究了温度对气凝胶复合材料导热的影响,结果表明,气凝胶复合材料的导热系数随温度的升高逐渐增大,900℃导热系数为室温的5倍。研究了气体环境对气凝胶复合材料导热的影响,发现氮气环境下气凝胶复合材料的导热系数随温度的变化与空气环境基本相同。

Silica sol was used as precursor to prepare silica aerogel composites by using RTM technology.The structure characterization of the aerogel composites was carried out.The thermal insulation and temperature resistance of aerogel composites were tested,the results show that the back temperature of 20 mm thick material is 186℃after 900℃and 1000 s quartz lamp test,the linear shrinkage of material is 1.2%after 1000 s muffle furnace test at 1100℃,the aerogel composites have excellent thermal insulation and temperature resistance.The effect of temperature on the thermal conductivity of aerogel composites was studied,the results show that the thermal conductivity of aerogel composites increases with the increase of temperature,the thermal conductivity at 900℃is 5 times of the thermal conductivity at room temperature.The influence of gas environment on the thermal conductivity of aerogel composites was studied,the results show that the thermal conductivity of aerogel composites in nitrogen environment is basically the same as that in air environment.