Binary solvent mixture for tape casting of TiO2 sheets

Four azeotropic binary solvent mixtures based on ethanol/methyl ethyl ketone, ethanol/toluene, isopropanol/methyl ethyl ketone and isopropanol/toluene were studied for the dispersion of TiO2 powders. Two different polyvinyl butyral polymers (PVB79 and PVB98) were selected as dispersant and as binder and dibutyl phthalate (DBP) was used as plasticizer. The dispersability of TiO2 suspensions was characterized by rheological measurements and sedimentation tests. After tape casting, the properties of Green tapes were tested in term of density, surface roughness and strength. Results showed that azeotropic EtOH/MEK mixture is the effective solvent system for tape casting of TiO2 sheets. The TiO2 tapes served for multilayer ceramic/metal composite manufacturing.