Various rare-earth-doped α-SiAlON powders with high purity were prepared to study
mechanical and optical properties of SiAlON-based functional materials in connection with ionic
radius and electronic structure of rare-earth elements. Single phase rare-earth-doped α-SiAlON
powders were obtained at a temperature as low as 1873 K by heating powder mixtures of rare-earth
oxide, AlN and highly active ultrafine amorphous Si3N4.
Bending strength of highly dense rare-earth-doped α/β-SiAlON-based ceramics was increased
with decreasing radii of rare-earth ions, i.e., Yb-SiAlON-based ceramics exhibited excellent
high-temperature strength and oxidation resistance caused by the small ionic radius of ytterbium.
As for optical application, α-SiAlON is an excellent host lattice with good thermal and chemical
stability for doping rare-earth element which activates photoluminescence. Europium-doped
Ca-α-SiAlON phosphor formulated as CaxEuy(Si,Al)12(O,N)16 (where 0