The stabilization of wet foam is an important parameter for obtaining a large volume of dried foams in porous ceramics. Octalymine (CH3(CH2)7NH2) is used as a foam stabilizer, which modifies the particle surface, improves the colloidal and rheological properties of the suspension, improving the wet foam stability with a tailored bubble size. The characterization of SiC foams, including the contact angle, surface tension and adsorption free energy, Laplace pressure, foam stability, air content, bubble size, and relative bubble size are explored by changing the concentration of the ampliphile. Adsorption free energy of 1.5 × 10−15 J to nearly 1.4 × 10−14 J, and Laplace pressure of 0.52 mPa to 0.25 mPa, good wet foam stability of more than 80%, was prepared by direct foaming. Macroporous SiC ceramics with open or closed cells, an average pore size of 350 μm, 41.5% porosity and compressive strength up to 0.7MPa were obtained when the sample was sintered at 2150 oC for 1 hr.

Keywords: Colloidal suspension, Surfactant, Direct foaming, Wet-foam stability, Porous ceramics