Thermal insulation of 3D printed complex and miniaturized SiO2 aerogels at medium-high temperatures

•Printable silica aerogel ink configuration.•Gain silica aerogels with complex shapes by DIW.•Study the thermal insulation performance of silica aerogels with different types and contents of opacifiers at medium-high temperatures. Due to aerogel's network structure, specific surface area, and high porosity, SiO2 aerogel has excellent thermal insulation and inferior mechanical properties. It is challenging to produce micro-objects and complex-shaped objects accurately by traditional manufacturing method because of the fragile mechanical properties. Here, we use 3D printing to fabricate SiO2 aerogels. At the same time, we add opacifiers to reduce the aerogel's medium-high temperature thermal conductivity. The thermal conductivity of the SiO2 aerogel printed in the experiment is as low as 0.028 W/(m·K) at room temperature. The aerogel doped with 10 wt% SiC has the best thermal insulation at medium-high temperatures. And the 3D printed aerogel doped with 10 wt% SiC has a compression performance of 1.19 MPa, which is more than 10 times better than the usual aerogel. This paper provides a method for creating micro-objects and complex-shaped objects with excellent medium-high temperature thermal insulation using Direct Ink Writing (DIW).