GRAIN-GROWTH KINETICS IN ALUMINA-ZIRCONIA (CEZTA) COMPOSITES

Grain growth kinetics in alumina-rich, zirconia-alumina composites hav e been examined as a function of volume fraction of zirconia. Both the microstructural scale and character alter during grain growth. Grain growth exponents between n = 3 and 4 were observed and have been ratio nalized in terms of current models for grain growth and particle coars ening. Grain growth constants were measured and compared with availabl e data. Coupled grain growth was observed in that the ratio of the alu mina-to-zirconia grain size was constant, for a given zirconia content . This behavior is discussed in terms of the topological constraint pr esent during growth and the observed microstructural evolution. The me asured activation energies were consistent with boundary-diffusion-con trolled grain growth.