Novel silica-modified boehmite aerogels and fiber-reinforced insulation composites with ultra-high thermal stability and low thermal conductivity |
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| Affiliation: | 1. Federal University of São Carlos, Graduate Program in Materials Science and Engineering (PPGCEM), 13565-905 São Carlos, SP, Brazil;2. Federal University of São Carlos (UFSCar), Department of Materials Engineering (DEMa), 13565-905 São Carlos, SP, Brazil;3. Université Paris-Saclay, CentraleSupélec, ENS Paris-Saclay, CNRS, LMPS – Laboratoire de Mécanique Paris-Saclay, 91190 Gif-sur-Yvette, France;1. Science and Technology on Advanced Ceramic Fiber and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China;2. Department of Material Science and Engineering, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China;1. Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410073, PR China;2. Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, United Kingdom;1. School of Civil Engineering, Beijing Jiaotong University, 100044, Beijing, China;2. Institute of Advanced Structure Technology, Beijing Institute of Technology, 100081, Beijing, China;1. Tongji University, Shanghai 200092, PR China;2. Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092, PR China;3. School of Electronics and Information Engineering, Tongji University, Shanghai 200092, PR China |
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| Abstract: | Alumina–silica composite aerogels have drawn vast attention due to their enhanced thermal stability compared to pristine alumina aerogels. However, they are generally weakly-crystallized and tend to experience inevitable sintering and significant surface area loss especially above 1200 °C. In this study, we developed a hydrothermal treatment and supercritical drying strategy for synthesizing novel, well-crystallized, silica-modified boehmite aerogels and fiber-reinforced composites. For the prepared aerogel, network coarsening was significantly hindered and the α-Al2O3 transition was completely prevented even at 1400 °C. As a result, the aerogel exhibits extremely high surface area maintenance (87 % and 53 % after 1300 °C and 1400 °C calcination, respectively) and low linear shrinkage (14 % after 1300 °C calcination) at elevated temperatures. The composite with good toughness shows excellent heat resistance and thermal insulating performance up to 1500 °C. These findings provide a general, direct new idea to improve the thermal tolerance of alumina-based aerogels and extend their applications to higher temperatures. |
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| Keywords: | Silica-modified Alumina aerogel Hydrothermal treatment Thermal stability Composite |
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