Large-scale and ultra-low thermal conductivity of ZrO2 fibrofelt/ZrO2-SiO2 aerogels composites for thermal insulation

The large-scale fibrous/aerogels composites are prepared by using zirconia fibrofelt (ZFF) as skeleton to give high strength and ZrO2-SiO2 aerogels (ZSA) as filler to give excellent thermal insulation through vacuum impregnation. The ZFF/ZSA with a low density of 0.302 g/cm3 and a high porosity (89%) exhibits large size of 180 mm in length, 180 mm in width and 25 mm in height which is larger than other fibrous aerogels. Meanwhile, the ZFF/ZSA exhibits high compressive strength of up to 0.17 MPa which is approximately six times higher than that of ZFF (0.028 MPa). The ZFF/ZSA shows a much lower thermal conductivity of 0.0341 W m−1 K−1 at room temperature and 0.0460-0.096 m−1 K−1 during 500 °C and 1100 °C which are lower than that of conventional fibrous materials, indicating its excellent thermal insulation property in a wide temperature range, and the thermal insulation mechanism is analyzed. Thus, the large-scale, low density, high strength, and low thermal conductivity of ZFF/ZSA composites show enormous potential application in the fields of architecture, engineering pipes and aerospace for thermal insulation and protection.