Nanocrystalline YAG powders and translucent ceramics by wet-chemical method

By using the mixture of aluminum and yttrium chloride and ammonium hydrogen carbonate (AHC) or ammonia water (AW) as the reagent and precipitants, respectively, the nanocrystalline yttrium aluminum garnet (YAG) powder was synthesized by the co-precipitation method. The precursor obtained through the AHC method completely was transformed to YAG phase after calcining at 900??C for 2 h, and no intermediate YAM or YAP phase was detected during calcining. YAG powders obtained by calcining the carbonate precursor at 1100??C are well dispersed, the primary particle diameter is about 80 nm and the YAG powders have high sinterability. Translucent YAG ceramics were fabricated after vacuum sintering at 1700??C for 5 h using 0.5% tetraethyl orthosilicate(TEOS) as sintering aid addition. YAP phase is formed during calcing the hydroxide precursor by AW method. The resultant YAG powders are severely agglomerated and caused low density of the sintered body.EI081272-12771