Preparation of Porous Corundum/Mullite Ceramics by Sol-Gel Combined with Foaming Method

摘要

With silica sol and alumina powders as raw materials,porous corundum/mullite ceramics were prepared by sol-gel reaction combined with mechanical foaming.The in-situ solidification of the foam slurry containing silica sol was realized through the addition of NH4Cl solution.The results show that the gelation time of ceramic slurry decreased with concentration increasing of NH4Cl.XRD results showed that the phase compositions of samples were corundum and mullite.Typical microstructures of porous ceramics were connected pores with cell-window structure.The compressive strength of the porous samples with 80％ porosity was above 22MPa.