Deflocculants for tape casting of TiO2 slurries

Five dispersants, polycondensed fatty acid, castor oil, phosphate ester, polyvinyl butyral (B79), polyvinyl butyral (B98) are used as dispersant. The dispersability of TiO2 slurries is studied through ESA measurement, rheological characterization and FTIR test. ESA measurement shows that the adsorption of PVB79 and phosphate ester is of physical and chemical type, respectively. Rheology, TG–DTA and sedimentation measurements show that in the absence of binder, PVB79 is the best dispersant; after the addition of binder, phosphate ester is the best one. The adsorption of dispersants on powder surface is also characterized by FTIR. The dispersion and stability mechanism is discussed.