DRYING KINETICS OF WATER-BASED CERAMIC SUSPENSIONS FOR TAPE CASTING

An experimental study is described which seeks to characterise the dry ing kinetics of water-based ceramic (alumina) suspensions in controlle d environments. The drying process of the ceramic suspensions is shown , to a first approximation, to follow a two stage mechanism (initial s tage: 'external' evaporation controlled process; and second stage: 'in ternal' diffusion-controlled process). It has been shown that the temp erature, the humidity and the surface area of the samples strongly aff ects the drying kinetics of these suspensions in the initial stage of the drying. The thickness of the samples is more influential in the se cond stage of the drying. There are no noticeable effects of the initi al solid content and the nature of binder content of the suspensions o n the drying kinetics. A first order empirical relationship is provide d in order to predict the drying time and drying curve for these ceram ic suspensions. The drying curves of tape cast suspensions is shown to be predicted accurately by the use of this relationship. (C) 1998 Els evier Science Limited and Techna S.r.l. All rights reserved.