Pore structure evolution during solvent extraction and wicking

Abstract

Pore structure evolution and binder distribution during both solvent extraction and wicking were investigated for plastic-formed ceramic bodies. The solvent extraction rate had a t(-1/2) dependence, while the wicking rate varied depending on the degree of saturation. There existed a debinding front separating the debinded region (with pendular state) from the undebinded region (with fluid state) during solvent extraction, while the green body went through sequential transitions of capillary structure as a whole during wicking with the help of the rapid re-distribution of the binder system. In fact, the debinding process by wicking could be divided into four regimes: (i) the rapidly falling rate regime up to capillary state, (ii) a constant rate regime up to the funicular state, (iii) the first slowly falling rate regime To the pendular state, and (iv) the second slowly falling rate regime by evaporation and diffusion.