Impregnation molding of particle-filled preceramic polymers: Process modeling

A process model is presented for the analysis and simulation of impregnatio n molding of particle-filled, continuous-fiber ceramic composites. A multid imensional, transient particle filtration formulation is coupled with isoth ermal, anisotropic Darcy flow to predict filler-concentration profiles duri ng molding. The particle filtration is insensitive to the injection flow ra te; however, in irregularly shaped molds, the geometry of the mold greatly influences the local velocities, which results in local variations in the r ate of filtration. Although the preform volume fraction and inlet particle concentration influence the particle accumulation quantitatively, the filtr ation coefficient and the permeability have a dominant role in setting the filtration trend.