Fabrication of tailored ceramics by colloidal processing and their application

Two types of tailored ceramics were prepared by colloidal processing. First, colloidal processing was applied to obtain dense and homogeneous alumina- and zirconia-based ceramics with fine-grained microstructure. Large tensile elongation exceeding 550% was achieved for 10 vol.% zirconia-dispersed Al2O3 at 1773 K and high-strain-rate (above 10(-2) s(-1)) superplastic zirconia-based ceramics were achieved by adding TiO2 and MgO. In the second process, a high magnetic field was applied during slip casting of alumina suspension to produce textured microstructure. A green body with a slight degree of crystallographic orientation was obtained and the degree of texture increased as temperature was increased. After densification, alumina grains grow to yield ceramics with textured grains and high degrees of crystallographic orientation. This processing can be applied to other ceramics having asymmetric unit cell, such as SiC, Si3N4, etc.