Kinetic modelling of binder burnout for optimisation of slurry-powder manufacturing process of Ti/SiC composites

Abstract

A slurry-powder metallurgy method is currently under development as a low cost production route for Ti/SiC composites. One of the critical steps in the process is the complete removal of a fugitive binder used to form the powder slurry. A diffusion-controlled, shrinking-core model has been developed for the prediction of the binder burnout kinetics in a metal powder compact with relatively large particles. This model is suitable for a polymeric binder that decomposes mainly to a monomer. The model considers the degradation of the polymer and the diffusion of the monomer in the core that contains a powder structure filled with a liquid polymer-monomer solution. It is found that the dominant mechanism is the liquid diffusion of monomer and the burnout time increases significantly with the compact size. The model also predicts a longer burnout time for a larger particle volume fraction. © 2000 IoM Communications Ltd.