The effect of porosity development on the removal of organic vehicle from ceramic or metal moldings

An experimentally verified model, which quantifies the degradation and diffusion of organic vehicle during pyrolysis of a ceramic molding in the shape of an infinite cylinder, has been modified to accommodate the various effects of porosity development as degradation proceeds. Thus, in the first case, a shrinking radius has been taken into account as organic matter recedes. Secondly, the formation of uniformly distributed porosity is considered as organic vehicle is removed. In each of these instances, the model predicts the critical heating rate and temperature at which boiling occurs in the ceramic body, giving rise to internal defects for various cylinder radii.