Pressure casting of silicon nitride
article
This report deseribes the consolidation behaviour of Si3N4 dispersions during pressure casting. Dispersions of two Si3N4 powders were uni—dimensionally pressure cast at different pressure levels, up to 8 MPa, both in a flocculated and a deflocculated state. The flocculated slips resulted in much more compressible cakes, with lower specific hydrodynamic resistances compared to the deflocculated slips. The porosity of a flocculated consolidated layer was always higher than that of a deflocculated layer, even when much higher pressures had heen used to form the flocculated cake. This type of compressible cake became conical after drying. It was shown that dispersions with a dilatant behaviour result in products with higher porosities at higher pressures. The quadratic equation describing the filtration process was also valid when a compressible consolidated layer was processed. From the Kozény-Carman equation a specific permeability surface area was calculated. For the deflocculated cakes this specific permeability surface was in good agreement with the measured BET specific surface area when the Kozény constant was taken to be 5.
TNO Identifier
282223
Source
Journal of the European Ceramic Society, 7, pp. 307-314.
Publisher
Elsevier
Collation
8 p.
Place of publication
London
Pages
307-314
Files
To receive the publication files, please send an e-mail request to TNO Repository.