PORE STRUCTURE EVOLUTION DURING SOLVENT-EXTRACTION AND WICKING

Pore structure evolution and binder distribution during both solvent e xtraction and wicking were investigated for plastic-formed ceramic bod ies. The solvent extraction rate had a t(-1/2) dependence, while the w icking rate varied depending on the degree of saturation. There existe d a debinding front separating the debinded region (with pendular stat e) from the undebinded region (with fluid state) during solvent extrac tion, while the green body went through sequential transitions of capi llary structure as a whole during wicking with the help of the rapid r e-distribution of the binder system. In fact, the debinding process by wicking could be divided into four regimes: (i) the rapidly falling r ate regime up to capillary state, (ii) a constant rate regime up to th e funicular state, (iii) the first slowly falling rate regime To the p endular state, and (iv) the second slowly falling rate regime by evapo ration and diffusion.