Fluid Flow Model for Ceramic Tape Casting

The flow behavior of a ceramic slurry during tape casting is analyzed based on the principles of fluid dynamics. The fluid model yields explicit expressions for tape thickness as a function of viscosity, the pressure gradient, and the speed and geometry of the casting head. The theoretical predictions are verified by experiments using a perovskite slurry as the testing material. The results show that within the range of normal operating conditions a uniform tape thickness can readily be achieved. Furthermore, it is feasible to maintain a high speed casting operation without any deleterious effect on the tape quality. The fluid flow process in a casting head with a non-parallel exit channel is also examined. In this case the ceramic slurry experiences a much higher pressure than that cast through a parallel channel and this higher pressure would enhance particle alignment, especially for anisotropic powders, in the resultant ceramic tape.