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1997
Conference Paper
Titel
Druckguß und Gelcasting als defektarme Gießtechnologien im Vergleich mit Pulverpreßverfahren
Abstract
The optimization of granule structure and processing may reduce the size and frequency of defects in the form of relicts of agglomerates in the sintered microstructures, but it is impossible to avoid such flaws in approaches that use agglomerated powders. As a consequence, the strength of sintered alumina products is limited to 400-500 MPa with uniaxial pressing or to 500-650 MPa after cold isostatic pressing. On the contrary, liquid shaping procedures associate an improved homogeneity of the power structure in the "green" bodies with a reduced sintering temperature and enable a higher strength of 500-750 MPa when no or only very small binder concentrations are used (e.g. in pressure filtration). Even more homogeneous green structures and a yet higher strength of 700-900 MPa can be obtained by gelcasting due to the polymerization of monomer binders.