An unoriented three dimension framework (network) of fibrous porous ceramics prepared by freeze casting

Freeze casting was used to fabricate unoriented three dimension framework of fibrous porous ceramics. Compared with vacuum filtration, this method was helpful in keeping the original three-dimensional dispersion which led to both high porosity and strength. The results indicated that the optimum fibers and silica sol content were 2 vol% and 5 wt% respectively for mechanical and other properties. The high-temperature stability of fibrous porous ceramics prepared by freeze casting and vacuum filtration are discussed in this paper. The samples showed lower thermal shrinkage and better stability because of the three dimensional orientations under a high temperature environment with a pressure of 0.8 MPa. The maximal tolerable temperature of samples preparing by freeze casting had been as high as 1200 °C.