Microstructure and Compressive Properties of Porous Zirconium Silicate Ceramics Prepared by Gelcasting and Mechanical Foaming

Porous zirconium silicate ceramics were successfully prepared using industrial zircon as raw material and 0.1vol.%-0.5vol.% C12H25OSO3H·N(C2H4OH)3 aqueous solution (Surf-E) as foaming agent via gelcasting and mechanical foaming method.The rheological behavior of slurries and the phase,fracture morphology and compressive properties of the porous ceramics were characterized by arheometer,X-ray diffractometer,scanning electron microscope and material tester.The result show that the slurry with 0.5vol.% foaming agent (Surf-E )and 0.2wt.% thickener (CMC) showed the best rheological behavior.After high temperature sintering,the porous zirconium silicate ceramic was of tetragonal structure ZrSiO4 with little monoclinic structure ZrO2.The cellular structure was nearly spherical with average size of 100 μm while the cell wall was rugged.The average compressive strength of porous ceramic with a density of 1.83 g·cm-3 and porosity of 54.3% was about 24.6 MPa.