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以陶瓷纤维制成的高温隔热瓦为骨架,真空浸渍氧化铝溶胶,再经过凝胶、老化和超临界干燥制备出氧化铝气凝胶复合高温隔热瓦,研究了其在不同温度处理后(最高温度1 400℃)的微观结构、隔热和力学性能。结果表明:气凝胶复合高温隔热瓦在1 400℃保温30 min后线收缩率仅为2%;随着热处理温度升高,气凝胶颗粒发生熔并、长大,气凝胶从填充纤维空隙到不断收缩,但对纤维骨架没有明显影响;隔热瓦的室温、高温热导率均显著降低;在热面1 400℃的背温测试中,复合后材料的背温从945℃降到870℃;复合后隔热瓦的力学性能略有增加;但是1 200~1 400℃的压缩强度下降较大。可见,气凝胶复合高温隔热瓦可改善其隔热性能,但在高温下力学性能下降。
A high-temperature insulated tile made of ceramic fiber was used as the framework, the alumina sol was impregnated in vacuum, and then aerogels composite high-temperature insulated tiles were prepared by gelation, aging and supercritical drying. (Maximum temperature 1400 ℃) microstructure, thermal insulation and mechanical properties. The results showed that the linear shrinkage of the airgel composite high temperature heat-insulating tile was only 2% after it was kept at 1 400 ℃ for 30 min. As the heat treatment temperature increased, the airgel particles fused and grew, The shrinkage of the fiber voids continued but no significant effect on the fiber skeleton; the thermal conductivity at room temperature and high temperature of the insulation tile significantly decreased; in the back temperature test of 1 400 ℃ on the hot surface, the back temperature of the composite material decreased from 945 ℃ To 870 ℃; the mechanical properties of the composite thermal insulation tile slightly increased; however, the compressive strength decreased greatly from 1 200 ~ 1 400 ℃. Visible, airgel composite high temperature insulation tile can improve its thermal insulation properties, but the mechanical properties at high temperatures decline.