Numerical simulation of organic binder decomposition during thermal debinding

In several powder technological processing routes debinding of green parts can be critical due to possible damage formation. Especially large parts or very dense compacts in combination with higher thermal heating rates are vulnerable. In this paper we present a model which describes the chemical decomposition of organic binders and the consequential development of an internal gas pressure. It includes the combined Maxwell-Stefan and Knudsen diffusion and the seepage flow of multiple gaseous reaction products through a porous body. The model is implemented into the finite element program ABAQUS. The internal stresses developing due to this gaseous overpressure during decomposition are shown for some simple examples. Predicting these stresses can indicate critical temperature regions and help to optimize debinding conditions.