Shape Forming via Colloidal Isopressing: Reformulating a Commerical Silicon Nitride Slurry with a Commercial Silane

Abstract : Colloidal Isopressing is a new shape forming method that requires a pre-consolidated slurry with a flow stress much less than that of a commercial throwing clay (< 0.1 MPa), so that it can be injected into a rubber cavity and isopressed. It is shown that the desired interparticle pair potential can be achieved with a commercial silane for a commercial Si3N4 aqueous slurry (NT 154-X12) containing densification aids. Unlike previous work, this silane has a relatively short molecular length and unlike previous results, the addition of salt was not needed to shorten the molecule and achieve the rheological behavior after pre-consolidation. The results of this study also show that the transition from a fluid-like to elastic-like behavior after consolidation was related to the relative density achieved during the pre-consolidation step, which was dependent on the consolidation pressure.