Formation and calcination temperature-dependent sintering activity of YAG precursor synthesized via reverse titration method

The composition homogeneity of YAG precursors synthesized via both normal and reverse titration co-precipitation methods is discussed. It was demonstrated that that the reverse titration process possesses better co-precipitation characteristics than the normal titration process, based on a real-time monitoring of the reaction pH and measurement of the Y/Al ratio in the precipitate. The formation process of the precipitate obtained by reverse titration method was discussed. The effect of calcination temperature on sintering properties of the YAG powder was investigated by analysis of the crystalline phase, the specific surface area, and the morphology of the powder. The shrinkage rate test of compacts made from different powders indicates that a higher calcination temperature results in a lower densification speed and shrinkage ratios. Microstructure observation shows that the ceramics made from YAG nanopowder, which was obtained at a higher calcination temperature, have a more uniform grain-size distribution and fewer residual pores. (C) 2010 Elsevier B.V. All rights reserved.