Study on Dispersion Stability of SiC Slurry and Its Membrane Properties

Silicon carbide (SiC) slurry with a low concentration was prepared, which was milled for 3 hours by mixing SiC powder with a certain amount of polyethylene glycol (PEG), tetramethyl ammonium hydroxide (TMAH), carboxymethyl cellulose sodium (CMC-Na), distilled water, and ethonal. The influence of the pH value on the Zeta potential and the additional components on the dispersion stability of the slurry were analyzed. The influence of various factors on slurry was studied by orthogonal experiment. The results showed that solid content had the greatest influence on viscosity and stability of slurry. After the slurry was coated on the surface of porous SiC ceramics and sintered at high temperature to form a SiC membrane, the micro-structure of SiC membrane and its pore size were characterized. The result showed that the pore size distribution of SiC membrane was narrow, and the average pore diameter was about 1µm. Meanwhile, the resultant grains tend to be round, uniform, single phase. Based on the above, we could know that the slurry has a good membrane-forming properties.