氧化铝气凝胶隔热材料的制备和热学性能  

Synthesis of Thermal Insulation Material Alumina Aerogels and Thermal Properties

作　　者：隗小庆[1] 倪星元[1] 沈军[1] 祖国庆[1] 张志华[1] 杜艾[1] 

机构地区：[1]同济大学波耳固体物理研究所,上海200092

出　　处：《材料研究学报》2012年第3期261-266,共6页Chinese Journal of Materials Research

基　　金：国家科技支撑计划2009BAC62B02资助项目~~

摘　　要：以仲丁醇铝为前驱体,以硝酸为催化剂,采用溶胶-凝胶法在室温条件下制备出半透明且无明显裂纹的块体氧化铝气凝胶,密度为120 kg/m^3。用场发射扫描电镜、HotDisk热分析仪、孔径分布仪、X射线衍射仪以及FT-IR红外光谱仪表征了氧化铝气凝胶的结构和热学性能,并根据气凝胶的微结构解释了传热机制。结果表明:所制备的气凝胶是一种多晶勃姆石相明显的纳米多孔材料,具有由球状颗粒组成的多级孔洞纳米网络结构。这种多级结构极大降低了气凝胶的热传导,其常温热导率低至0.020 W/m·K。Translucent, crack-free monolithic alumina aerogels were prepared at room temperature by sol-gel method combined with the ethanol supercritical drying technique using alumina tri-sec butoxide and nitric acid as the precursor and catalyzer respectively. Hydrolysis and condensation were controlled in different steps. The density of the derived aerogel is 120 kg/m^3. The micro-structure and thermal properties of the alumina aerogels were analyzed by SEM, XRD, FT-IR, thermal analyser （Hotdisk） and pore size distribution analyser. The heat transfer mechanism was explained from different aspects of aerogels＇ micro--structure. The results show that the alumina aerogels prepared by this method are materials with obvious polycrystalline of boehmite phase and nano-sized multi-hole network structure with spherical particles, which grately reduced the gas and solid thermal conductivity. The total thermal conductivity of the aerogels obtained is 0.020 W/m.K at room temperature.

关 键 词：无机非金属材料 氧化铝气凝胶 溶胶-凝胶 低热导率 多级孔洞结构 

分 类 号：TB321[一般工业技术—材料科学与工程]