Fabrication and properties of mullite fiber matrix porous ceramics by a TBA-based gel-casting process

A bird nest-like structure was designed by using the mullite fiber as the matrix and SiO2 as the high temperature binder. This special material was successfully prepared by a TBA-based gel-casting process. The randomly arranged fiber laps bonded by SiO2 binder was the most important structure characteristic of this porous material. The effect of sintering temperature on the properties, i.e. porosity, bulk density, linear shrinkage, compressive strength, thermal conductivity and the microstructure was studied. The composite exhibited significant pseudoductility. The fracture mechanism of this composite under compression was discussed. The results indicated that the sintering temperature ranging from 1500 to 1600 °C was suitable for yielding mullite fiber matrix porous ceramics which had a low thermal conductivity (0.19–0.22 W/m K), a relatively high compressive strength (3–13 MPa) and a high resilience (66–70%) for applications in the thermal insulators and high-temperature elastic seal field.