Thermal insulation characteristics of a lightweight, porous nanomaterial in high-temperature environments
Thermal insulation characteristics of a lightweight, porous nanomaterial in high-temperature environments
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DOI：
10.1016/j.matdes.2017.11.059
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发表时间：
2018-02-15
影响因子：
8.4
通讯作者：
Wu, Wenjun
中科院分区：
文献类型：
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作者：
Ren, Haoyuan;Wu, Dafang;Wu, Wenjun
纳米隔热材料具有优异的隔热性能，是航天器用热防护材料的一种。本研究利用自主研发的高速航天器热测试系统，通过实验研究了轻质多孔氧化铝（Al2O3）纳米材料的高温隔热特性，并通过数值模拟进行了计算。结果表明，在1200℃的正面高温环境下，厚度仅10毫米的Al2O3纳米材料片材可降低温度70%以上，同时表现出稳定的隔热性能。这表明Al2O3纳米材料具有优异的高温隔热性能。扫描电镜（SEM）图像显示，温度超过1200℃后，Al2O3纳米颗粒的聚集和生长加速，单个Al2O3纳米颗粒和孔隙尺寸明显增大；此外，材料内部的纤维开始熔化，裂纹的数量、深度和宽度开始显着增加。此外，Al2O3纳米材料片的边缘发生了明显的收缩和弯曲变形；因此，Al2O3纳米材料适合在1200℃以下的热环境中使用。研究结果为航天器热防护系统的设计提供了重要的参考依据。 (C) 2017 Elsevier Ltd. 保留所有权利。
Thermal-insulating nanomaterialswith excellent thermal insulation performance are one type of thermal protection material used in spacecraft. In this study, the high-temperature insulation characteristics of a lightweight, porous aluminum oxide (Al2O3) nanomaterial were studied through experimentation using a self-developed thermal testing system for high-speed spacecraft, and were calculated by numerical simulation. The results showed that in a 1200 degrees C front-surface, high-temperature environment, an Al2O3 nanomaterial sheet with a thickness of only 10 mm could reduce the temperature by over 70% while exhibiting stable thermal insulation performance. This demonstrates that the Al2O3 nanomaterial has excellent high-temperature insulation performance. The scanning electron microscopy (SEM) images showed that, after the temperature exceeded 1200 degrees C, the aggregation and growth of the Al2O3 nanoparticles accelerated, and single Al2O3 nanoparticles and voids increased significantly in size; in addition, the fibers inside the material started to melt, and the cracks started to increase considerably in number, depth, andwidth. Furthermore, a significant contraction and bending deformation occurred at the edges of the Al2O3 nanomaterial sheet; therefore, the Al2O3 nanomaterial is suitable for use in a thermal environment below1200 degrees C. The results provide an important reference basis for the design of thermal protection systems for spacecraft. (C) 2017 Elsevier Ltd. All rights reserved.