Elaboration of Yttrium Aluminum Garnet (YAG) nanopowders and ceramics: Comparison between batch and plug-flow reactor

In this study YAG (Y₃Al₅O₁₂) nanopowders have been synthetized by a reverse co-precipitation method with two different designs of reactors: batch and plug-flow. The impact of both the reactor design and the synthesis temperature on the features of nanopowders so-synthetized was studied. The reactor design governs the pH evolution and precipitation kinetics during synthesis. Correlations were found between the reactor design and nanopowders stoichiometry and morphology. The plug-flow reactor allows obtaining homogeneous, well-crystallized and single-phased YAG nanopowders after calcination. Then, the sintering ability of as-obtained nanopowders was investigated. Fully dense YAG-based ceramics were obtained with the nanopowders made from the plug-flow reactor by combining uniaxial pressing and sintering at 1700 °C. Finally, a plug-flow reactor with very simple and inexpensive design would allow easier upscale of the synthesis process of YAG-based nanopowders with well-controlled morphology and stoichiometry. As a result, YAG based transparent ceramic were obtained without sintering additive.