Han Lujia, Chen Shile, Li Honghua, Dong Yanhao, Wang Chang-An, Li Jiangtao
Key Laboratory of Cryogenics Science and Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
University of Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2024 Aug 13;15(1):6959. doi: 10.1038/s41467-024-51278-w.
Ceramic aerogels are promising materials for thermal insulation and protection under harsh environments. Yet current synthesis methods fail to provide an energy-, time-, and cost-effective route for high-throughput production and large-scale applications, especially for non-oxide ceramic aerogels. Here we reported a way to synthesize SiC aerogels within seconds and over liter scale, with a demonstrated throughput of 16 L min in a typical lab experiment. The key lies in renovated combustion synthesis and a fast expansion from powder reactants to aerogel products over 1000% in volume. The synthesis process is self-sustainable and requires minimal energy input. The product is very cheap, with an estimated price of ~$0.7 L ($7 kg). The obtained SiC aerogels have excellent thermo-mechanical properties, including low thermal conductivity, high elasticity, and damage tolerance. Our invention not only offers a practical pathway for large-scale applications of ceramic aerogels, but also calls for rethinking of combustion synthesis in one-step conversion from raw chemicals to bulk products ready for practical applications.
陶瓷气凝胶是用于恶劣环境下隔热和防护的有前景的材料。然而，目前的合成方法未能提供一条用于高通量生产和大规模应用的节能、省时且经济高效的途径，特别是对于非氧化物陶瓷气凝胶而言。在此，我们报道了一种在数秒内合成数升规模碳化硅气凝胶的方法，在典型的实验室实验中展示了约16升/分钟的产量。关键在于改进的燃烧合成以及从粉末反应物到气凝胶产物超过1000%的体积快速膨胀。合成过程是自我维持的，且所需能量输入极少。该产品非常便宜，估计价格约为0.7美元/升（约7美元/千克）。所获得的碳化硅气凝胶具有优异的热机械性能，包括低导热率、高弹性和损伤容限。我们的发明不仅为陶瓷气凝胶的大规模应用提供了一条实用途径，还促使人们重新思考从原始化学物质一步转化为可用于实际应用的块状产品的燃烧合成。
