Fabrication of cordierite glass ceramics by slip casting of glass powders

Glass powders of cordierite composition were prepared for slip casting and the effects of particle size distribution, solids content, type and amount of various deflocculants, and slip pH were investigated on the properties and rheological behaviour of prepared slips. All the slips showed both thixotropic and dilatant behaviour, the latter predominating to differing extents. By employing a wide particle size distribution and 0-1 wt-% sodium tripolyphosphate as a deflocculant, stable slips of 77-5 wt-% maximum solids content were prepared and successfully cast in plaster moulds. After determination of suitable heat treatment temperatures by DTA, the specimens were soaked for I and 2 h at 760 and 1200° C for nucleation and sintering crystallisation stages respectively. In this way cordierite glass ceramics of 95% theoretical density and bend strength of 72 MPa were obtained. BCT/291