Tape casting using UV curable binders

High-density tapes were obtained by tape casting of a slurry composed of alumina powder, dispersant, UV curable binder and photoinitiator, and by subsequent photopolymerization. The use of a photopolymerizable binder offers the advantage of eliminating the drying stage, which is a critical step of the tape casting process. The effects of the solid loading, of the dispersant and photoinitiator concentrations and of the temperature on the rheological behaviour of the slurries were investigated Both addition of dispersant and photoinitiator had a positive effect on the rheology of the slurries. The highly loaded alumina suspensions (82 wt%, i.e. 57 vol%) exhibited a shear-thickening behaviour, which was not detrimental in this solvent-free process because of the possibility of hardening the sheet instantly, by polymerization, just after casting. Near ly theoretical densities (98.9%) were obtained after sintering at 1540 degrees C of the irradiated alumina tapes. (C) 1997 Elsevier Science Limited.