Quartz fiber reinforced Al2O3-SiO2 aerogel composite with highly thermal stability by ambient pressure drying

摘要

A low-cost and high-performance quartz fiber/Al2O3-SiO2 aerogel (QF/ASA) composite insulation material has been successfully prepared by vacuum filtration molding and sol-gel impregnation following surface-modified ambient pressure drying (APD). The macroporous in the quartz fiber perform are filled by Al2O3-SiO2 aerogels with a large amount of mesoporous. The morphology, microstructure, thermal conductivity and thermal stability of the QF/ASA composite were investigated. Compared to the fiber/aerogel materials dried by supercritical drying, the composite exhibits similar low density (0.36 g.cm(-3)), high specific surface area (580.5 m(2).g(-1)), low thermal conductivity (0.049 W.m(-1).K-1) at room temperature. The compressive strength of the composite up to 0.85 MPa which is approximately triple as much as that of fiber perform. After being heated at 600 to 1100 degrees C, the specific surface area of composite aerogel decrease from 578.0 to 113.6 m(2).g(-1) and the linear shrinkage is almost zero. The XRD patterns show that mullite (3Al(2)O(3)center dot 2SiO(2)) appeared in the Al2O3-SiO2 aerogel after heat treatment at 1100 degrees C, which is consistent with the molar ratio of silica and alumina of 2:3.