Mechanism of low thermal conductivity of xonotlite-silica aerogel nanoporous super insulation material

作     者：Hailong Yang Wen Ni Deping Chen Guoqiang Xu Tao Liang Li Xu 

作者机构：Civil and Environmental Engineering School University of Science and Technology Beijing Beijing 100083 China 

出 版 物：《Journal of University of Science and Technology Beijing》 (北京科技大学学报（英文版）)

年 卷 期：2008年第15卷第5期

页      面：649-653页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 070301[理学-无机化学] 

基　　金：the National High-Technology Research and Development Program of China (863 Program No2003AA302610) 

主　　题：silica aerogel xonotlite nanometer-sized pore super insulation thermal conductivity 

摘      要：In an effort to incorporate the low thermal conductivity of the silica aerogel and the superior structure strength of the xonotlite,a composite material of these two was produced. It was synthesized under vacuum condition and dried by supercritical drying technique. The thermal conductivity of the new material,which is at 298K with the gas pressure ranging from 1.01×10^5 to 1×10^-2 Pa,was measured using the transient hot-strip method. The mechanism of the low thermal conductivity was studied. The results indicate that the low thermal conductivity mainly results from the significant decrease of gaseous thermal conductivity of the new material due to the restriction of the motion of gas molecules in its fine structures. The formation of the fine structures is because the new material takes the pore structure of the silica aerogel which consists of mainly nanometer-sized pores.