Synthesis of nano-sized yttrium-aluminum Garnet in a continuous-flow reactor in supercritical fluids

Abstract

The conditions for obtaining pure yttrium-aluminum garnet (YAG) in a one-step process starting from components soluble in supercritical (SCR) liquids in a flow reactor have been studied. The powders were characterized using XRD, BET, SEM and helium pycnometry. Favorable conditions for YAG production were achieved using acetates (and acetylacetonates) in aqueous-alcoholic solutions as starting materials. Aqueous and alcoholic solutions of nitrates and aqueous solutions of acetates were found not appropriate as precursors for YAG production. The powders obtained had the shape of nano-sized cubes with diameters in the range 80-120 nm. After annealing at 600°C the powders have comparable density as those made via a conventional precipitation-calcination route but differ from the calcinated products form soft agglomerates. © 2008 Verlag der Zeitschrift für Naturforschung. Tübingen.