纳米SiO2多孔陶瓷的绝热性能

摘要

Nanoporous silica ceramics were prepared with infrared opacifiers to improve the thermal insulating performance at high temperature.Microstructure and thermal insulating properties were characterized by field emission scanning electron microscopy（FESEM）,specific surface area and porosity analyzer,Fourier transform infrared（FT-IR） spectroscopy and temperature measurement,etc.Mechanism of infrared opacifiers was also investigated.When 20wt % K2Ti6O13 with an average particle size of 1.07 μm is added,the maximum value of effective specific extinction coefficient increases from about 19.5m2/Kg to 60.6m2/Kg and the cold side temperature decreases from 252℃ to 148.9℃ when the hot side temperature of the samples is maintained at 600℃.Results show that infrared opacifiers can effectively scatter and reflect infrared radiation and significantly increase effective specific extinction coefficient and then improve thermal insulating properties of nanoporous silica ceramics at high temperature.%本文制备了纳米SiO2多孔陶瓷材料,并引入红外遮光剂提高其在高温下的绝热性能。利用场发射扫描电镜、比表面积及孔隙度分析仪、傅里叶红外分析仪和背温试验等方法对该材料的微观结构及绝热性能进行分析,并重点研究了红外遮光剂的作用机理。当添加质量分数为20%、平均粒径为1.07μm的六钛酸钾（K2Ti6O13）作为遮光剂时,试样的最大有效消光系数从19.5m2/Kg提高到60.6m2/Kg,热面温度为600℃的试样的背面温度从252℃降低到148.9℃。红外遮光剂的加入能有效散射和反射红外辐射,显著提高试样的有效消光系数,改善该材料的高温绝热性能。