Al2O3–TiO2/ZrO2–SiO2 based porous ceramics from particle-stabilized wet foam

The porous ceramics based on Al 2 O 3 –TiO 2 /ZrO 2 –SiO 2 from particle-stabilized wet foam by direct foaming were discussed. The initial Al 2 O 3 –TiO 2 suspension was prepared by adding TiO 2 suspension to partially hydrophobized colloidal Al 2 O 3 suspension with equimolar amount, to form Al 2 TiO 5 on sintering. The secondary ZrO 2 –SiO 2 suspension was prepared using the equimolar composition, and to obtain ZrSiO 4 , ZrTiO 4 , and mullite phases in the sintered samples, the secondary suspension was blended into the initial suspension at 0, 10, 20, 30, and 50 vol%. The wet foam exhibited an air content up to 87%, Laplace pressure from 1.38 to 2.23 mPa, and higher adsorption free energy at the interface of approximately 5.8×10 8 to 7.5×10 8 J resulting an outstanding foam stability of 87%. The final suspension was foamed, and the wet foam was sintered from 1400 to 1600 °C for 1 h. The porous ceramics with pore size from 150 to 400 μm on average were obtained. The phase identification was accomplished using X-ray diffraction (XRD), differential thermal analysis (DTA), and thermogravimetric analysis (TGA), and microstructural analysis was performed using field emission scanning electron microscopy (FESEM).