Texture Development in Alumina Composites by Slip Casting in a Strong Magnetic Field

Abstract

Magnetic susceptibility is very small in feeble magnetic ceramics such as alumina, consequently, it had been very difficult to develop a textured microstructure in these ceramics by using a magnetic field. We have demonstrated, however, that textured microstructures in alumina, titania, zinc oxide can be prepared by colloidal processing in a high magnetic field followed by sintering. We applied this processing technique to alumina based composites. The degree of crystallographic texture was small in specimen sintered at the low temperature. The degree of orientation increased rapidly with increasing sintering temperature and depended on the grain size of alumina matrix. The grain size can be controlled by the content of YTZ particle as a second phase, the kind of dopant, sintering temperature, annealing temperature and annealing time.