SYNTHESIS AND DENSIFICATION OF TRANSPARENT POLYCRYSTALLINE CERIUM-DOPED YTTRIUM ALUMINUM GARNET (YAG)

Transparent doped YAG ceramics are used for many different applications including phosphors and solid state lasers. The sintering process typically requires two or more stages which involve high temperatures, long dwell times or vacuum atmospheres. In the current work, nano-powders were synthesized by a co-precipitation method from a mixture of metal nitrates solutions and ammonium hydroxide as the precipitation agent. The synthesized product was freeze-dried to produce a fine amorphous powder that later underwent calcination at 750^°C. Spark plasma sintering (SPS) densification technique was used for the fabrication of dense, highly transparent polycrystalline doped YAG at relatively low temperatures and short dwell times. SPS is shown to produce highly transparent cerium-doped YAG (Ce:YAG) with excellent optical properties. Such material could be used, for example, as a yellow phosphor in white light emitting diodes.