耐高温达 1600 °C 的基于 Alpha Al2O3 纳米片的双相气凝胶,ACS Applied Materials & Interfaces

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耐高温达 1600 °C 的基于 Alpha Al2O3 纳米片的双相气凝胶
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2023-01-24 , DOI: 10.1021/acsami.2c20272
Qiyan Ji ₁ , Li Zhang ₁ , Xiuling Jiao ₁ , Dairong Chen ₁

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氧化铝气凝胶是轻质和高效隔热材料的理想选择。然而，它们通常受到高温下脆性和结构坍塌的限制。制造具有超低导热性和在超过 1300 °C 的高温下具有出色热稳定性的氧化铝气凝胶仍然具有挑战性。在此，通过以硅溶胶作为高温粘合剂组装α-Al ₂ O ₃纳米片，成功制备了具有优异的耐超高温性和隔热性的氧化铝气凝胶。得益于莫来石覆盖的氧化铝双相结构的产生，α-Al ₂ O ₃基于纳米片的气凝胶 (ANSA) 即使在高达 1600 °C 的高温下煅烧后也表现出优异的热稳定性和化学稳定性。ANSA 具有低导热系数 (0.029 W·m ^–1 ·K ^–1室温下），结构稳定，抗压强度实测为0.6 MPa，抗热震性好。此外，还制备了二维 α-氧化铝@莫来石核壳片作为组装单元来构建气凝胶 (AMSA)。这种核壳结构可以在高温下连续输入能量的情况下通过晶格间抑制来提高耐温性。AMSAs在1600℃煅烧30分钟后线性收缩率仅为2.7%，进一步提高了耐温性，使其成为极高温应用的理想超级绝缘材料。

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Alpha Al2O3 Nanosheet-Based Biphasic Aerogels with High-Temperature Resistance up to 1600 °C

Alumina aerogels are desirable for lightweight and highly efficient thermal insulation. However, they are typically constrained by brittleness and structural collapse at high temperatures. The manufacture of alumina aerogels with ultralow thermal conductivity and excellent thermal stability at high temperatures beyond 1300 °C is still challenging. Herein, alumina aerogels with superior ultrahigh-temperature-resistant and thermal insulation were successfully prepared by assembling the α-Al₂O₃ nanosheets with silica sols as the high-temperature binders. Benefiting from the generation of the mullite-covered alumina biphasic structure, the α-Al₂O₃ nanosheet-based aerogels (ANSAs) exhibit excellent thermal and chemical stabilities even after calcination at as high as 1600 °C. The ANSAs had a low thermal conductivity (0.029 W·m^–1·K^–1 at room temperature), structural stability with a measured compressive strength of 0.6 MPa, and good thermal shock resistance. Furthermore, the 2D α-alumina@mullite core–shell sheets were also prepared as assembly units to construct aerogels (AMSAs). This core–shell structure can improve temperature resistance through inter-lattice suppression under continuous energy input at high temperatures. The AMSAs have a linear shrinkage of only 2.7% after calcination at 1600 °C for 30 min, further improving the temperature resistance, making them an ideal super-insulating material for applications at extremely high temperatures.

更新日期：2023-01-24

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