Development of SiAION: From Mechanical to Optical Applications

摘要

Various rare-earth-doped α-SiA;ON 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 Si_3N_4. Bending strength of highly dense rare-earth-doped α/β-SiA10N-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 Ca_xEu_y(Si,Al)_(12)(O,N)_(16) (where 0