Design of Packing Structures through Direct Characterization of Ceramics Green Bodies

(Review)

Abstract

The design of processing procedures for ceramics should be based on an accurate knowledge of the packing structures in the green compacts, as these govern the structures of the ceramics after sintering and thus their properties. We examined packing structures by a variety of methods and we studied processing methods for improving these structures. Granules in dry-pressed compacts were examined by confocal laser scanning microscopy. The humidity during pressing and the type of binder significantly affect the deformation behavior of the granules and thus the structure of the compact. The strength of the sintered body increases with increasing homogeneity of the green body. The structures of the particle orientation were also examined by polarized-light microscopy of green compacts made by slip casting. The degrees of orientation were quantitatively evaluated through the measurement of retardation. The anisotropy thus evaluated was dependent on the particle shape and the draining condition of water during shaping. Particles of near-spherical shape produced homogeneous structures.