Abstract
Cerium-doped alpha'-SiAlON material was prepared by spark plasma sintering at 1750 C under 30 MPa pressure for 10 min. Yttrium alpha'-SiAlON seeds (1 wt%) were added to the starting powder mixture. Recent work showed that up to 45 wt% of alpha'-SiAlON phases are formed in the sintered ceramics. The material showed a microstructure containing rodlike cerium-doped alpha'-SiAlON crystals. TEM and EDS were used to analyse the alpha'-SiAlON grains. The structural analyses revealed a high density of domain boundaries, within which larger amounts of Ce ions were segregated. The density of the domain boundaries was proportional to the amount of incorporated Ce ions. These structural defects eventually dominated the growth habits of the alpha'-SiAlON crystals, by modifying the structure of the interstices at the boundary sites. The role of yttrium alpha'-SiAlON seeds is also discussed. 16 refs.