Herein, a novel and simple approach for directly growing nanowire-built nanofibrous ceramic foams with tunable hierarchical pores has been put forward, where silicon particles, Ludox® and carbon black are selected as the initial materials. Firstly, cellular green bodies were constructed by freeze casting method, and their oriented pores provided sufficient but designated space for the generation of nanowires during carbothermal reduction nitridation process, meanwhile ensured the adequate nitrogen supply. The prepared multi-laminate ceramic foams assembled by nanowires with low density of 0.40 g/cm³ exhibit excellent heat insulation performance with low thermal conductivity of 0.12 W/(m·K) and outstanding dielectric properties with low dielectric constant of 2.35 at frequency of 10.0 GHz, which could be attributed to the hierarchical porous structure built by nanowires level by level, and they would have promising applications in the thermal insulators, absorptions, catalyst supports, filters for gas or liquid as well as wave-transparent materials.

在此，提出了一种新颖且简单的方法来直接生长具有可调层次孔隙的纳米线构建的纳米纤维陶瓷泡沫，其中选择了硅颗粒，Ludox®和炭黑作为初始材料。首先，通过冷冻浇铸法制备细胞生坯，其定向孔为碳热还原氮化过程中纳米线的产生提供了足够但指定的空间，同时确保了充足的氮供应。通过低密度为0.40 g / cm ^3的纳米线组装的制备的多层陶瓷泡沫 在10.0 GHz频率下具有出色的隔热性能，低导热系数0.12 W /（m·K）和出色的介电性能以及2.35的低介电常数，这可归因于纳米线逐级构建的分层多孔结构，它们将在绝热材料，吸收剂，催化剂载体，气体或液体过滤器以及波透明材料中具有广阔的应用前景。