Dynamic study of ammonium dawsonite doped with yttrium transformation at elevated temperatures

Abstract

Co-precipitation of alumina/YAG precursor from aluminum and yttrium nitrates solution with ammonium carbonate results in dawsonite (NH 4Al(OH)2CO3). Its crystallographic parameters differ from the compound precipitated without the yttrium additive. It indicates that yttrium ions become incorporated into the dawsonite structure. The DSC/TG and X-ray measurements show decomposition of dawsonite at elevated temperature resulting in γ-Al2O3 which transforms to δ and θ modifications at still higher temperatures. The full transformation to α-Al2O3 and YAG occurs at temperatures higher than 1,230 C. © 2012 The Author(s).