Lightweight porous silica ceramics with ultra-low thermal conductivity and enhanced compressive strength

In recent years, the need for robust thermal protection for reusable spacecraft and vehicles has spurred strong demand for high-performance lightweight thermal insulation materials that exhibit high strength. Herein, we report silica porous ceramics prepared via the direct foaming technique with lightweight, ultra-low thermal conductivity and enhanced compressive strength. Silica particles (particle size: 500 nm and 2 mu m) were used as the raw materials. The nano-sized silica particles were easily sintered, thereby improving the compressive strength of the ceramics, whereas the micro-sized silica particles maintained the pore structure integrity without deformation. The addition of nano-silica enhanced the compressive strength by 764% (from 0.039 to 0.337 MPa). In addition, the thermal conductivity of the ceramics was as low as 0.039 W m-1 K-1. Owing to these outstanding characteristics, these porous silica ceramics are expected to be employed as thermal insulation material in diverse fields, especially aerospace and space where weight is an important constraint.

Automated summary

The demand for high-performance lightweight thermal insulation materials in reusable spacecraft and vehicles has led to the development of porous silica ceramics with lightweight, ultra-low thermal conductivity, and enhanced compressive strength. By using different sizes of silica particles, the compressive strength and pore structure integrity of the ceramics were improved. These ceramics have a very low thermal conductivity and are suitable for use as thermal insulation materials in aerospace and space applications.