Synthesis and properties of lightweight fibrous ceramics with a 3D skeleton structure prepared by infiltration

In our report, a fibrous ceramics with the mullite fibers as the matrix and SiO2-AlPO4 sol as the high-temperature binder were fabricated by the infiltration method. The effects of sintering temperature on the properties, such as porosity, phase transition, microstructure, compressive strength and fracture mechanism, were investigated. Compared with the fibrous ceramics with the SiO2-B2O3 binder, the fibrous ceramics with the SiO2-AlPO4 binder exhibited lower densities (0.560-0.595 g/cm3), lower thermal conductivities (0.157-0.165 W/mK), high strain (7-8%), high rebound-resilience (77-90%) and the same level of compressive strengths (1.1-2.1 MPa). During the cooling stage of the heat treatment process, α→β-cristobalite displacive phase transition in the SiO2-AlPO4 binder was successfully suppressed. The fracture behavior of the ceramics tends to be a layer-by-layer failure, which is quite different from that of the traditional ceramics. The non-brittle fracture mode and the excellent elasticity made this fibrous ceramics promising high-temperature elastic insulation materials.