UV curable systems for tape casting

The substitution of solvents by photopolymerizable binders in the tape cast ing process allows to achieve high ceramic loading and to eliminate the dry ing stage which is a critical step of the tape casting process. After the r apid UV polymerization of the resin, the high strength green tapes can be d ebinded and sintered. Ceramic suspensions containing alumina or zirconia po wder, dispersant, UV curable binder and photoinitiator have been prepared. The use of a low viscosity organic vehicle allows to prepare low viscosity ceramic suspensions, containing about 50 vol% powder, which have a shear th inning behaviour. Because of the rapid attenuation of the incident light in UV curing systems containing ceramic particles it is important to estimate the thickness of the tape that can be treated. The effect of incident ener gy, of photoinitiator concentration and of powder volume fraction was studi ed. There is an optimal photoinitiator concentration which maximizes the cu red depth and which depends on the volume fraction of solid. A theoretical model based on the Beer-Lambert's law enables the prediction of cured depth for any volume fraction of solid. To prove the ability to manufacture cera mic sheets by tape casting, some suspensions were tape cast. (C) 1998 Elsev ier Science Limited. All rights reserved.