Novel fibrous/nano-Al2O3 insulation composites produced using sol-gel impregnation for energy-saving

The fibrous/nano-Al2O3 insulation composites had high porosities (78.35–81.30%) and low thermal conductivities (0.084–0.159 W m−1 k−1 at 200–600 °C).In addition, the inclusion of nano-Al2O3 resulted in a well-structured hierarchical pore distribution, which facilitated multidirectional heat transfer paths and ultimately led to a marked reduction in thermal conductivity of the samples.Moreover, the fibers were overlapped to create a three-dimensional structure, while the nano-powders were dispersed in the liquid phase and cross-linked to generate a spatial mesh structure.